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It is the end of women's menstrual periods. Menopause is a natural event, not an illness. The menopause generally comes in late fifties. Menopause can mark the end of many pressures and the start of greater vitality and freedom. In some women, menopause signs are irregular, and scanty.

It is a progressive bone disease that is characterised by a decrease in bone mass and density which can lead to an increased risk of fracture. In osteoporosis the bone mineral density is reduced. This is most common in women after menopause.

Osteoporosis: Low Estrogen Levels & Poor Nutrition, Especially low calcium intake makes bone porous.

                                    or

Osteoporosis is a weakening of the bones due to the loss of bone density and improper bone formation.

There is no cure for Osteoporosis. There are a few steps to prevent, such as by getting enough calcium and vitamin D, which are essential for bone health. Medication is advised only from all expert doctor.

There is higher risk of bone fracture or further disability. There can be sudden back pain and risk of falling. Because of fall there is increased risk of wrist, spine, shoulder and hip fracture. There is also a balance disorder and movement disorder.

It is of thee types.

(a) Type I

(b) Type II

(c) Secondary Osteoporosis,

Type I: It is mainly in females after menopause. 

Type II: It is both in females and males after 7-5 years of age at 2 : 1 ratio. 

Secondary Osteoporosis: It may appear at any age because of prolonged use of medication or pre-medical history.

Cold wash is recommended for new / coloured cotton fabrics. Cold water, due to its higher surface tension, does not penetrate deep into the fibres and thus does not fade the colours.

Hot water, because of its lower surface tension, can penetrate deep into fabric fibres and remove tough stains.

Role of Diet on performance: The energy quality of sports diet depends on correct proportion of carbohydrates, proteins, fats, vitamins. salt and minerals which are the main nutrients of the diet. 

(a) Proteins: Proteins are the main building foods and form the main constituents of muscles, tissues and blood. They supply the building material for the body during the growth process and also repair the wear and tear of muscles, ligaments and tendons. Hence, they are must essential for an athlete. The ideal sports diet should have both animal and vegetable protein in adequate quantities. 

(b) Carbohydrates: They form the main bulk of a sportsman's diet and are the main sources of energy for physical activities. These are the sources of  'instant energy' for athletic activities. This is the reason why athletes are advised to take glucose during physical activities. Glucose should be taken in specific dilution in water by those who are physically active. Atleast 50% to 60% of calories should come in the form of carbohydrates. 

(c) Fats: Fats are considered a major source of fuel for light to moderate level of activity. There is different proposition of fat requirement for maximum performance, For example there is normal fat requirement for distance runner. high jumper and a gymnast because if they add weight it will hinder their performance. 

(d) Minerals: Excessive sweating during exercise, especially in hot climate, causes loss of optimum amount of sodium and potassium from the body. Hence, fruit Juices should be added to the fluids taken during and after exercise. Iron requirement of Indian athletes is comparatively higher due to increased sweating. chances of worm infestation. etc. 

(e) Vitamins: During sports activities. the need for various vitamins, particularly vitamin A, vitamin B complex and vitamin C increases. In sports vitamins are often used against one's better judgement in the hope of improving performance. Drink small volume of water frequently rather than large volumes infrequently e.g.,6-8 ounces every 15 minutes. Water makes 70% of our body weight. Sports persons should drink enough water to replace the water they lose through sweating.

During the early part of ancient Olympics, women were not allowed to witness or compete in games and sports. It was basically considered that women were physically less active than men in all age groups and were under-represented in sports, both in active membership and in management positions. At the same time, women's participation in sports can improve sport, as sport can improve the quality of life. Women are less represented than men in the active membership of sports clubs and a positive discrimination of women in different roles varies widely, but in most cases, men dominate in the total membership, especially in management and administration and various other committees. 

However, in Modern Olympic Games, no restriction was made for their participation in sports competitions but due consideration was given while assigning athletic events keeping in view anatomical and physiological differences in their physique. The participation of women for the first time in Olympic was in 1900 Paris Olympic in few events, where only 12 women participated but in 2000 Sydney Olympics women participated in almost all events. 

During the early 1970s, female athletics underwent a dramatic revolution. Demands were made for equality in budget, facilities, equipment, coaching and competitive opportunities for a position in the world of athletics comparable to that enjoyed by the males. No doubt that men's performances are better than women's. Males and females differ in body built, body composition. motor skills and energy system

Concept of sports sociology: Sports is a social institution having its own distinctive value orientations, important social concerns, modes of interactions and strategic structural relationships with other significant social institutions. Sport is a strong social force in our culture. It is important to society as it affects the behaviour of human beings and institutions. When sportsmen engage in games/sports, they express socialized relationship. Socialization in sports and games reveals personal and social characteristics of a sportsman. 

Importance of Sociology in sports: 

(a) It helps in emotional release of tension. 

(b) It offers opportunities to be recognized and to express one's Individual qualities. 

(c) It creates a communal spirit that brings people together in a cohesive manner. 

(d) It allows the interaction with all kinds of people.

Women in sports has been a topic virtually ignored by most scholars and thus female sports participation has been a relatively undeveloped area of research. Sex role, stereotyping, male research. Bias and the reward structure of society have contributed to the neglect. Currently sports for women represents a fast growing changing element in Indian culture, and recent trends have sparked a need for knowledge about the female sports participation. Constraints of women participation in sports in India due to parental, community to tradition, religion, college and personal constraints and pressures. 

Female athlete triad:

It is a syndrome in which eating disorder such as Anaemia, oestoporosis (decreased bone mineral density) and amenorrhoea are present. This condition is seen in females that emphasize leanness or low body weight. The Triad is serious illness with life long health consequences and can potentially be fatal. 

It is a medical condition where a body does not have enough Red Blood Cells or haemoglobin. It occurs mainly due to nutritional deficiencies especially Iron. 

Any long term medical condition can also lead to anaemia. 

(a) Less iron in diet. 

(b) Heavy menstrual periods are most common cause in women. 

(c) Pregnant women may also become anaemic. 

(d) Genetic defect (sickle cell anaemia) 

(e) Risk increases in old age. 

(f) There is high risk to become anaemic among those who are suffering from Kidney disease, cancer etc. 

Treatment of Anaemia depends on its causes and severity. 

(a) Iron deficiency anaemia is treated with change in diet and iron supplement. 

(b) Through medication and injections to stimulate bone marrow to produce more RBC. 

(c) Limit your activities until anaemia is corrected with iron therapy. 

(d) In case of severe anaemia, the person is hospitalized. 

It is a progressive bone disease that is characterised by a decrease in bone mass and density which can lead to an increased risk of fracture. In osteoporosis the bone mineral density is reduced. This is most common in women after menopause. 

There is higher risk of bone fracture or further disability. There can be sudden back pain and risk of falling. Because of fall there is increased risk of wrist, spine, shoulder and hip fracture. There is also a balance disorder and movement disorder. 

There is no cure for Osteoporosis. There are a few steps to prevent, such as by getting enough calcium and vitamin D. which are essential for bone health. Medication is advised only from an expert doctor. 

Amenorrhoea: It is absence of menstrual period in a woman of reproductive age. It is of two types-Primary and Secondary Amenorrhoea. In case of Primary Amenorrhoea, the menstrual cycle never starts (no menarche) and in case of Secondary Amenorrhoea, the menstrual cycle ceases or premature menopause occurs.

Causes of Amenorrhoea: 

(a) Insufficient eating, 

(b) Stress, 

(c) Weight loss, 

(d) Excessive exercises, 

(e) Induced drugs, 

(f) Lactational. 

Treatment depends upon the causes as well as health status of individual. It includes: 

(a ) Weight: Attaining and maintaining a healthy weight often helps balance harmone level and restores menstrual cycle. Overweight and severe underweight can affect menstrual cycle. 

(b) Stress: Reduce the things that are causing stress, asses the areas of stress and seek professional help. 

(c) Level of physical activity: Adjust physical activity level to help restart menstrual cycle. Maintain health, do not overstrain the body. 

(d) Birth control pills: or other types of hormonal medication may help restart the menstrual cycle. 

(e) Estrogen Replacement therapy ERT: It may help balance hormonal levels and restart the menstrual cycle in women. 

(d) There is 'surgical treatment for secondary Amenorrhoea.

Anorexia Nervosa: It is a complex eating disorder. When someone tries to keep his/her weight as low as possible, we call it as immoderate food restriction and irrational fear of gaining weight. People suffering from this disease typically involve excessive weight loss. This restriction of food intake causes metabolic and hormonal disorders. 

Symptoms: 

(a) dieting even when underweight 

(b) drastic weight loss 

(c) lying about eating 

(d) under stress 

(e) taking only low calorie nutrition 

(f) hair loss 

(g) constipation, etc. 

Treatment: 

All people with anorexia need treatment. It includes: 

(a) Medical treatment: Doctors will treat the medical condition caused by anorerra such as osteoporosis, stress, depression, etc. In case of severe malnutrition a person is hospitalized.

(b) Counselling: A dietitian will help you take charge of your weight in a healthy way. He/she will make proper plan and will build trust in you. You are made confident of attaining good health. 

(c) Proper post-treatment: Follow the medical treatment prescribed by doctor. Do not cheat yourself. Take control of your eating habits, build trust in people who are helping you. Leave the bad thoughts and start again because health is in your hands. Proper treatment is necessary to come back to your original health status.

There are two types of Bulimia. Purging induces vomiting when a person consumes large amount of food rapidly whereas in non-purging Bulimia a person skips meals or abstains from food and aims to reduce weight.

Anorexia nervosa is an eating disorder characterised by immoderate food restriction and irrational fear of gaining weight, as well as distorted body self-perception. It typically involves excessive weight loss and usually, occurs more in females. Because of fear of gaining weight, those with this disorder restrict the amount of food they consume. This restriction of food intake causes metabolic and hormonal disorders.

An active lifestyle and exercise routine, along with eating well, is the best way to stay healthy. Eating a good diet with enough fluids can help provide the energy you need to finish a race or just enjoy a casual sport or activity. You are more likely to be tired and perform poorly during sports when you do not get enough calories, carbohydrates, fluids, vitamins, iron and other minerals, and protein. 

Daily Training Diet Requirements 

(1) Enhance adaptation and recovery between training sessions. 

(2) Promote the short and long-term health of athlets. 

(3) Provide adequate fluids to ensure maximum hydration before, during and after exercise. 

(4) Provide enough energy and nutrients to meet the demands of tainting and exercise. In your diet, include a wide variety of foods like wholegrain bread and cereals, vegetable (particularly leafy green varieties), fruits, lean meat and low-fat dairy products to enhance long term nutrition habits and behaviors. To know the role of particular diet, it would be better to know the role of essential nutrients on performance. These essential nutrients are described below:

Protein 

Proteins are a part of our tissues including body fluids such as blood, they are needed for repair and maintenance of body tissues. Proteins are essential for muscular development. All sportsmen require a good amount of protein in their diets. However, sportsmen like boxers and wrestlers require more proteins due to wear and tear of tissues. 

Fats

Fats are composed of fatty acids. These are a better sources of energy. Fat Provides heat end energy to the body. Athletes and sportsmen require fat from light to moderate proportions, because fat is a source of fuel or energy for the body. 

However, high jumpers or gymnasts require only minimum amount of fat, because the extra weight can hinder their performance.

Carbohydrates 

Carbohydrates are specially voluble food when a considerate amount of muscular work to be undertaken. Carbohydrate is an essential component of a sportsman’s diet because less intake of carbohydrates can result in exhaustion. Carbohydrates also provide strength and fuel for muscles. Therefore, an athlete’s diet should be rich in carbohydrates.

Vitamins

Vitamins accelerate the vitality, lightness, buoyancy and resistance of the body. Vitamins are essential for normal functioning of the body and good performance in sports. For example, Vitamin E helps in the treatment of heart diseases. Similarly, Vitamin C helps in the treatment of wounds.

The three Vitamins which have proved significantly are

Vitamin “B-Complex”. Deficiency of vitamin “B-Complex” has shown the decrease on the sports performance. Studies related to excess amount of Vitamin “B-complex” intake show both the improvement in performance and no influence on performance. So, there is further need for research to know the effect of this vitamin on the performance.

Vitamin “C”. Low level of Vitamin ‘C’ intake does not reduce the work performance significantly. Approximately,60 mg of Vitamin ‘C’ intake by non athletes and 300 mg to 500 mg intake by successful athletes do not have any harmful effect on kidneys.

Vitamin ‘E’. Vitamin ‘E’ has been claimed to have beneficial effects in the treatment of many diseases and specially heart diseases. Studies conducted on the use of vitamin ‘E’ have shown little or no effect on the performance.

Water 

In the diet of a sportsperson water is required as a solvent, a transport medium, a substrate in hydrolytic reactions and for lubrication. Water is an essential component of diet. Loss of water in the body can lead to nervous system disorder, headache and dizziness, However, excess amount of water does not show any improvement in performance. Thus every athlete/sportsperson should consume a wellbalanced diet incorporating all essential nutrients.

Minerals

Minerals are required in a sportsperson’s body for various functions. Sportsperson’s body requires essential minerals like iodine, iron, calcium, magnesium, phosphorus etc. During sports performance, sweating can reduce the amount of Sodium from the body. It can be compensated by the intake of salt. However, excessive intake of salt can lead to Potassium loss or water retention. Iodine is also required for the normal functioning of the thyroid gland. 

1) Range of molecular attraction or molecular range : Range of molecular aftraction or molecular range is defined as the maximum distance between two molecules up to which the intermolecular force of attraction is appreciable.

[Note : The intermolecular force is a short range force, LeV, it is effective over a very short range-about 10^.-9 m. Beyond this distance, the force is negligible. The inter molecular force does not obey inverse square law.

2) Sphere of influence : The sphere of influence of a molecule is defined as an imaginary sphere with the molecule as the centre and radius equal to the range of molecular attraction.

[Note : All molecules lying within the sphere of influence of a molecule are attracted by (as well as attract) the molecule at the centre. For molecules which lie outside this sphere, the intermolecular force due to the molecule at the centre is negligible.]

Let the pressure inside the balloon be and the outside pressure be P₀

P_i − P₀ = \(\frac{2T}{r}\)

[T = Surface Tension, r = radius balloon]

Considering the air to be an ideal gas

P_iV = n_iRT_i

Where, V is the volume of the air inside the balloon, n_i is the number of moles inside and T_i is the temperature inside, and P₀V = n₀RT₀ where V is the volume of the air displaced and n₀ is the number of moles displaced and T₀ is the temperature outside.

So, n_i = \(\frac{P_{i}V}{RT_i}=\frac{M_{i}}{M_A}\)

Where M_i is the mass of the air inside and M_A is the molar mass of the air and n₀ = \(\frac{P_0V}{RT_0}=\frac{M_0}{M_A}\) where M₀ is the mass of air outside that has been displaced. If W is the load it can raise, then

W + M_ig = M₀g

Or W = M₀g − M_ig

In atmospheric air, 21% O₂ and 79% N₂ is present.

∴ Molar mass of air

M_A = 0.21 × 32 + 0.79 × 28 = 28.84 g

∴ Weight raised by balloon

or W = \(\frac{M_AV}{R}(\frac{P_0}{T_0}-\frac{P_i}{T_i})\)g        here, P₀ = P_i

= \(\frac{0.02884× \frac{4}{3}π×8^3}{8.314}\) × 1.013 × 10⁵ (\(\frac{1}{293} − \frac{1} {333}\)) × 9.8 N

= 3044.2 N

Therefore, Mass lifted by balloon = \(\frac{W}{g}\)

= \(\frac{3044.2\, N}{9.8\frac{m}{s^2}}\)

= 310.6 Kg

Pressure at bottom ’of the trench = ρgh = 1.1 × 10⁸ Pa

Initial volume of the ball = 0.32 m³

Bulk modulus of steel = 1.6 × 10¹¹ Pa

Let ∆v the change in volume of Ball when it falls down to the bottom.

We know that, B = \(\frac{p}{(ΔV/V)}\)

⇒ ∆v = \(\frac {PV}{B}\)

= \(\frac{1.1 \times 10^8 \times 0.32}{1.6 \times 10^{11}}\)

= 2.2 × 10^-4 m³

Therefore, change in volume of the ball on reaching the bottom of the trench is 2.2 × 10^-4 m3 or 220 cm³.

Bulimia is a psychological disorder in which patient experiences regular bouts and serious over eating which are always followed by a feeling of guilt which can then lead to extreme reactions such as crash dieting, doing lots of exercise and purging. 

Types of Bulimia There are two types of Bulimia: 

(1.) Purging Bulimia: In this type of bulimia, the individual regularly engages in self-induced vomiting or the misuse of laxatives, diuretics or enemas. The individual rapidly wants to remove food from the body before it can be digested. 

(2.) Non-Purging Bulimia: In this type of bulimia, the individual uses other methods to get rid of calories and to prevent weight gain. She/he uses fasting, strict dieting or excessive but does not engage in self-induced vomiting or misuse of laxative, diuretics or enemas. 

Causes of Bulimia

(1) Performance pressure in sports: Eating disorders such as anorexia and bulimia are common among sportspersons. Usually gymnasts, racers and wrestlers are found to be affected by bulimia Coaches unknowingly contribute to eating disorders by encouraging sportspersons to reduce weight or maintain a low weight for presenting a better performance in sports. 

(2) Family history: Family history also plays a role in developing bulimia. Bulimia may develop to an individual whose parent, brother or sister has bulimia. It has some type of genetic link. 

(3) Psychological factor: Psychological factors such as low self-esteem, perfectionlism, impulsive behavior, depression and anxiety disorders etc. may be the causes of bulimia. 

(4) Social Factors: In fact, the persons who remain in media such as actors, dances and models are at higher risk of eating disorders. Such as bulimia and anorexia.

Symptoms of Bulimia 

(1) Makes excuses to go to the bathroom immediately after meals 

(2) Only eat diet or low-fat foods (except during binges) 

(3.) Regularly buy laxatives, diuretics, or enemas. 

(4) Fear weight gain. 

(5) Be intensely unhappy with body size, shape, and weight.

Treatment of Bulimia

(1) Healthcare provider should give a proper plan of physical activity or exercise to the person affected by bulimia. The affected individual should not perform excessive exercises to burn off calories consumed by taking more amounts of food. 

(2) Psychological treatment helps in improving symptoms of bulimia. Cognitive behavioral therapy can be used to treat mental ailments such as depression, negative beliefs and behaviors with healthy and positive ones. 

(3) In case of bulimia, to come back to a healthy weight should be given top priority. Dietician should prepare an eating plan to help you achieve a healthy weight. He should prepare an eating plan to help you achieve a healthy weight. He should provide education regarding normal eating habits and good nutrition. 

(4) Antidepressants may alleviate the symptoms of bulimia along with the psychotherapy or psychological treatment. Fluoxetine is the only antidepressant to treat bulimia.

Anorexia nervosa is a psychological disorder in which a patient has a distorted body image and an irrational fear of becoming overweight; therefore, they deliberately try to lose weight. 

Anorexia is of two types: purging type of anorexia and Restricting type of anorexia.

(a) Purging type of anorexia: Body weight is reduced due to vomiting or by taking laxatives. 

(b) Restricting type of Anorexia: Due to restricting calories, individual’s body weight is lost. 

Causes of anorexia: There may be various factors, and some of them are mentioned below:

Social Factors: Social pressures to remain thin can lead to anorexia. If an individual wants to participate in gymnastics or modeling, these professions demand to remain thin. In some cases, parents criticize their children’s bodies and appearance. This act of parents can lead the children towards anorexia. 

Biological factors: Biological factors are also cause of anorexia. If a female with anorexia has an offspring, that offspring is many times more likely to develop anorexia. 

Psychological factors: The affected people with anorexia are usually perfectionists. They do what they are told. They excel in every thing they do and focus themselves on pleasing others. But on the other hand they feel helpless inadequate and valueless. They never feel good enough.

Symptoms of Anorexia 

1. The individuals with anorexia are usually afraid of gaining weight. 

2. They follow dieting strictly despite being thin. They eat only-calorie foods. They avoid taking fats and carbohydrates in their diet. 

3. Such individuals just pretend to eat. They hide or throw away food to avoid eating. They make excuses to get out of meals. They can be heard of saying that they had a huge lunch or dinner or they are having some digestive problems. 

4. The individual also with anorexia usually refuse to eat in public places or party. If they eat, they eat in ritualistic ways e.g., chewing food and spitting it out etc. 

5. There is a rapid and drastic weight loss of the affected individual without any medial cause. The weight loss may be up to 15 percent of body weight.

6.Such individuals have a feeling of fat however they are underweight. They have a feelingthat they have excess fat deposited on their abdomen, hips and thighs. 

7.The affected individuals with anorexia usually take diet pill, laxatives or diuretics. At any cost they remain eager to reduce their body weight. 

8.They want to burn their calories more and more. Hence they do excessive exercise. Even when they are injured or ill, they definitely continue their exercise programme.

Prevention of Anorexia 

Following points can be taken care of for prevention of anorxia: 

1. They should say no to teasing or the teenagers should have concept that it is wrong to say hurtful things about another children’s body sizes. 

2. Fitness comes in all sizes. We must provide the knowledge to children about their genetics and body size. 

3. Stay away from the persons, places and activities which are related to anorexia.

Management and Treatment of Anorexia

For proper management and treatment the following points should be followed: 

1. Generally there are no medicines to treat anorexia effectively. However, antidepressants can help in treating other mental disorders such as depression or anxiety which are related to anorexia. 

2. Realize it that you have a problem of anorexia. Admit it that your relentless pursuit of thinness is out of your control. 

3. Individual psychotherapy can provide help to the affected person in dealing with the behavior and thoughts that lead to anorexia. He can gain a healthier self-esteem and learn positive ways to cope up with distress.

There are many causes of Bulimia. It can be genetic. Low opinion (self-esteem) about oneself can cause Bulimia as the person observes losing weight. Depression and psychological problems lead to the development of Bulimia, fashion industry and media environment creates interest in losing weight that may lead to Bulimia.

We know that the intermolecular distances between the gas molecules is quite large as compared to that of liquid.

Due to it the forces of cohesion in the gas molecules are very small and these are quite large for liquids. Therefore, the concept of surface tension is applicable to liquid but not to gases.

Given, L_v = 540\(\frac{kcal}{Kg}\)

= 540 × 10³ × 4.2 J/Kg

(a) Such that, 1kg of water requires energy for evaporation = L_v k cal

∴ M_A kg of water requires M_AL_vk cal

Since there are N_A molecules to evaporates is

\(u=\frac{M_AL_v}{N_A}J\)        [Here, N_A = 6 × 10²⁶ = Avogadro number]

= \(\frac{18×540×4.2×10^3}{6×10^{26}}\)

= 90 × 18 × 4.2 × 10^-23 J

= 6.8 × 10^-20 J

(b) Let us consider the water molecules to be points at a distance d from each other.

Volume of N_A molecules = \(\frac{M_A}{ρ_w}l\)

Thus, the volume around one molecule is \(\frac{M_A}{N_Aρ_w}l\)

The volume around one molecule is d³ = (\(\frac{M_A}{N_Aρ_w}\))

∴ d = \((\frac{M_A}{N_Aρ_w})^\frac{1}{3}\) = \((\frac{18}{6×10^{26}×10^3})^\frac{1}{3}\)

= (3 × 10⁻³⁰)^{\(\frac{1}{3}\)} m ≃ 3.1 × 10⁻¹⁰ m

(c) 1 kg of vapour occupies = 1601 × 10^-3 m³

∴ 18 kg of vapour occupies = 18 × 1601 × 10^-3 m³

or 6 × 10²⁶ molecules occupies = 18 × 1601 × 10^-3 m³

∴ 1 molecule occupies = \(\frac{18×1601×10^3}{6×10^{26}}m^3\)

If d₁ is the inter molecular distance.

Then

\(d^3_1\) = (3 × 1601 × 10^-29) m³

∴ d₁ = (30 × 1601)^{\(\frac{1}{3}\)} × 10^-10 m

= 36.3 × 10^-10 m

(d) To change the distance from d to d₁,

Work done = F(d₁ − d)

Work done = energy required to evaporate 1 molecule

Or F = \(\frac{6.8×10^{−20}}{d_1−d}\)

= \(\frac{6.8×10^{−20}}{ (36.3−3.1)×10^{−10}}\)

= 0.2048 × 10⁻¹⁰ N

(e) Surface Tension = \(\frac{F}{d}\)

= \(\frac{2.05×10^{−20}}{3.1×10^{−10}}\)

= 6.6 × 10^-2 Nm^-1

The height of the blood column in the human body is more at the feet than at the brain. As the pressure increases with the height of the column, blood exerts more pressure at the feet than at the brain (P = ρgh).

a) When air is blown under a paper, the velocity of air is greater under the paper than it is above it. As per Bernoulli’s principle, atmospheric pressure reduces under the paper. This makes the paper fall. To keep a piece of paper horizontal, one should blow over it. This increases the velocity of air above the paper. As per Bernoulli’s principle, atmospheric pressure reduces above the paper and the paper remains horizontal. 

According to the equation of continuity: Area × Velocity = Constant 

b) For a smaller opening, the velocity of flow of a fluid is greater than it is when the opening is bigger. When we try to close a tap of water with our fingers, fast jets of water gush through the openings between our fingers. This is because very small openings are left for the water to flow out of the pipe. Hence, area and velocity are inversely proportional to each other.

c) The small opening of a syringe needle controls the velocity of the blood flowing out. This is because of the equation of continuity. At the constriction point of the syringe system, the flow rate suddenly increases to a high value for a constant thumb pressure applied.

d) When a fluid flows out from a small hole in a vessel, the vessel receives a backward thrust. A fluid flowing out from a small hole has a large velocity according to the equation of continuity: Area × Velocity = Constant

According to the law of conservation of momentum, the vessel attains a backward velocity because there are no external forces acting on the system. 

e) A spinning cricket ball has two simultaneous motions – rotatory and linear. These two types of motion oppose the effect of each other. This decreases the velocity of air flowing below the ball. Hence, the pressure on the upper side of the ball becomes lesser than that on the lower side. An upward force acts upon the ball. Therefore, the ball takes a curved path. It does not follow a parabolic path.

cos θ = \(\frac{T_2-T_1}{T_3}\), where θ is the angle of contact for a liquid-solid pair, T₁ is the liquid-solid interfacial tension, T₂ is the solid-gas (air + vapour) inter-facial tension and T₃ is the liquid-gas interfacial tension.

Factors affecting a liquid-solid angle of contact: 

1. the nature of the liquid and the solid in contact, 

2. impurities in the liquid, 

3. temperature of the liquid.

a) Decreases

The surface tension of a liquid is inversely proportional to temperature.

b) Increases; decreases

Most fluids offer resistance to their motion. This is like internal mechanical friction, known as viscosity. Viscosity of gases increases with temperature, while viscosity of liquids decreases with temperature.

c) Shear strain; Rate of shear strain

With reference to the elastic modulus of rigidity for solids, the shearing force is proportional to the shear strain. With reference to the elastic modulus of rigidity for fluids, the shearing force is proportional to the rate of shear strain.

d) Conservation of mass/Bernoulli’s principle

For a steady-flowing fluid, an increase in its flow speed at a constriction follows the conservation of mass/Bernoulli’s principle.

e) Greater

For the model of a plane in a wind tunnel, turbulence occurs at a greater speed then it does for an actual plane. This follows from Bernoulli’s principle and different Reynolds’ numbers are associated with the motions of the two planes.

It means having difficulty in digesting a particular food. Intolerance to several foods or group of foods is the cause of chronic illness.

The angle of contact is acute when the solidgas (air + vapour) interfacial tension is greater than the liquid-solid interfacial tension.

Many children are not able to get all the nutrients they need for a balanced diet. Vitamins and minerals are essential nutrients that our body needs in small amounts to work properly. Those who do not take enough vitamins may suffer from vitamin deficiency and may have a risk of developing illness. Therefore, there is a need for food supplement to fulfill the requirement.

Vitamins: Vitamins are required by the body for its various metabolic processes and the normal working of the body. They are required by the body in very small amount. Vitamins do not yield energy but enable the body to use other nutrients. For a healthy person these requirements are met by a normal, well balanced diet. However, if our diet is lacking in any vitamin, we suffer from deficiency diseases. 

Vitamins are divided into two groups: 

(a) Fat-soluble vitamins (vit. A,D,E and K) 

(b) Water-soluble vitamins (vit. of B,C group) 

Each Vitamin has specific functions to perform. 

(a) Fat-soluble vitamins: 

Vitamin A: Vitamin A is essential for the construction of many different body tissues. It covers both retinol and beta carotene.

Functions: 

(i) It is indispensable for normal vision. It contributes to the production of retinal pigments which are needed for vision in dim light. 

(ii) It is necessary for normal functioning of glandular and epithelial tissue. 

(iii) It supports growth especially skeletal growth. 

(iv) It is anti-infective. 

(v) For keeping eyes and skin healthy. 

Sources: 

Food rich in retinol are liver, eggs, butter, cheese, whole milk, fish and meat. Vegetable sources are green leafty vegetable (spinach), yellow fruits, carrot and tomatoes (Red Pigment).

Deficiency of vitamin A is associated with skin damage and impaired resistance to infection, night blindness, Bitot's spots. 

Vitamin D: The nutritionally important form of vitamin D in men is calciferol. This conversion takes place partly in the liver and kidneys and partly in the skin under the influence of sunlight. Its function is to promote intestinal absorption of calcium. It is important for strong teeth. 

Sources: It is found in cheese, butter, milk, green vegetables, fish, liver oil and sunlight. Infants and small children have relatively high vitamin D requirement. Deficiency of Vitamin D in children causes rickets/abnormal growth and development of bones and overdosage of it may cause kidney or even brain damage. 

Vitamin E: It is found in vegetable oils, butter, milk, whole grain, corn. nuts, seeds and spinach. It is important to protect the cell membranes and also important in formation of Red Blood Cells (RBC). 

Vitamin K: It is found in cabbage, cauliflower, cereals, soyabean. spinach and other green leafy vegetables. vitamin K helps in clotting of blood. Deficiency of vitamin K causes excessive bleeding from wounds. 

Water-soluble Vitamins: These include vitamin B₁ B₂, B₃, B₁₂. and vitamin C. which are not stored by the body. 

Vitamin B: It is found in peanuts, fish, eggs, milk, cheese, peas. cereals and meat. Some of the complex vitamins are B₁ B₂ B₃. B₆ and B₁₂. These are all water-soluble and necessary for growth and development. Deficiency of vitamin B results in a disease called Beri-Beri, Pellagra, malformation of Red Blood Cells (RBC). 

Vitamin C: It is needed for the maintenance of the ligaments, tendons. and other supportive tissues and strong blood vessels. Vitamin C is found in amla, citrus fruits, tomatoes, green leafy vegetables and potatoes.

(a) Maintain your calorie balance 

(b) Avoid junk food 

(c) Eat healthy food items only 

(d) Avoid diet rich in fats 

(e) Eat lot of fruits and salad

(f)  Eat raw vegetables and fibre rich food 

(g) Avoid frequent consumption of carbonated beverages

The angle of contact is obtuse when the solidgas (air + vapour) interfacial tension is less than the liquid-solid interfacial tension.

Food intolerance means when an individual has difficulty in digesting a particular food. It is more common than food allergy. It can be tolerated a reasonable amount of food. It is not life threatening.

It means having difficulty in digesting a particular food. Intolerance to several foods or group of foods is the cause of chronic illness.

True. Angle of contact for a glass tube dipped in mercury is obtuse.

Food myths: These are unscientific reasons or thoughts about food items. These are more of a psychological nature than actual. Wrong information floats around nutrition and without knowing the logic we start following it or create myths without finding the truth.

It is an act of restricting one's food intake to maintain a controlled weight. The person who undergoes dieting is more likely to have eating disorder. We usually resort to dieting because we believe that being lean will make us look slim, trim and smart. So dieting is restricting what we eat or how much we eat in order to lose weight.

Maximum stress that can be taken by the off-share structure, 

P_max = 10⁹Pa. 

density of water = 10³ kg /m³ and g = 9.8 m/s² and h = 3km (depth of the sea)

∴ Pressure exerted by seawater, P = ρgh

= 10³ × 9.8 × 3 × 10³

P = 2.94 × 10⁷ Pa

Note that, P < P_max

Since the pressure exerted by the seawater is less than the maximum pressure the structure can withstand, the structure is suitable for putting on the top of the oil well.

(a) When a small quantity of liquid is poured in glass, three interfaces namely liquid-air, solid-air and solid-liquid are formed. The surface tensions corresponding to these three interfaces i.e., S_LA, S_SA and S_SL are related to angle of contact θ as,

cosθ = {S_SA - S_SA}/{S_LA}

In case of mercury glass, S_SA < S_SL, therefore, cosθ is in negative or θ > 0, obtuse. In case of water glass. S_SA > S_SL, therefore a cosθ is positive or θ < 90, i.e., acute.

(b) For mercury glass, angle of contact is obtuse. In order to achieve this obtuse value of angle of contact, the mercury tends to form a drop. In  case of water glass, the angle of contact is acute. To achieve this acute value of angle of contact, the wate tends to spread.

(c) Surface tension of liquid is the force acting per unit length on a line drawn tangentially to the liquid. Since this force is independent of the area of liquid surface; therefore, surface tension is also independent of the area of the liquid surface.

(d) We know that the clothes have narrow spaces in the form of capillaries. The rise of liquid in a capillary tube is directly proportional to cosθ. If θ is small, cosθ will be large. Due to which capillary rise will be more and so the detergent will penetrate more in clothes.

(e) In the absence of external forces, the surface of the liquid drop tends to acquire the minimum surface area due to surface tension. Since for a given volume, the surface area of sphere is least, hence a liquid drop takes the spherical shape.

Pitfalls of dieting are as follows: 

(a) The most common effect of dieting is hair loss. 

(b) The person remains under stress. 

(c) It can also lead to cognition impairment if continued for long. 

(d) The worst part of dieting is that it can even damage the organs of the body. 

(e) After dieting when you start eating your regular meal you gain weight very quickly and your physique is deformed.

Nutritive components: Nutritive components of diet are proteins, carbohydrates, fats, vitamins and minerals. 

Proteins: Proteins are nutrients that help to build the body and make new cells. They help us in repair of worn-out tissues. They are especially important for growing children. They are called bodybuilding food. Milk, eggs, cheese, pulses, meat and fish have lots of proteins. The daily requirement of proteins is about 20 gm. They help in maintenance of our muscles, tendons and ligaments.

Non-nutritive components: Water and fibres are non-nutritive components. 

Water: Almost two third of our body is made up of water. Water helps our body to work well and maintain body temperature. We need to drink at least 10-12 glasses of water everyday.

Food myths mean a legendary story about food with or without a determinable basic of fact or a natural explanation. What to eat, when to eat, and how often to eat are such questions which usually confuse.

Some food myths are as follows:

1. Potatoes make you fat
2. Drinking water in between your meals will mess up your digestion
3. Fat free products will help you in losing weight
4. Egg increases cholesterol levels
5. The peel of fruits & vegetables contains no nutrients
6. Having milk immediately after eating fish
7. Starve yourself if you want to lose weight
8. Eating ghee after pregnancy
9. Exercise makes you to eat more
10. It’s necessary to have Carbohydrate – load before races
11. All sports drinks are the same
12. Supplement are necessary for maximum performance

There are no advantage s of dieting. Science has proved that dieting causes many physical and mental problems. Your physique can even become worse than before. Some of the pitfalls of dieting are: 

(a ) Hair loss: The most common side effect of dieting is that you start to lose your hair. Lack of required amount of proteins and fats results in hair loss. 

(b) Depression: There are many other reasons of depression" Dieting is one among them. When your body is not able to handle loads of activities, you feel pressure in mind which causes stress. Stress worsens the mental as well as the physical health of a person. 

(c) Organs damage: If you continue dieting for a long time it can damage your internal organs and body systems. Its working efficiency decreases. Your blood circulation becomes passive. You are less energetic,lazy,lethargic and get weak. 

(d) Sudden weight gain: Weight loss through exercises is a good thing but weight loss through dieting is very harmful. It makes your physique worse because after dieting when you came to your original eating pattern your body starts gaining more fat than it used to before dieting.

(e) Dietary deficiency: When you cut short your diet, some of the major nutrients such as carbohydrates and proteins do not meet the required amount. This can lead to many deficiencies e.g., there are dark circles under eyes and the person looks pale. 

(f) Miscellaneous: Yet another pitfall of dieting is cognition impairment, sudden weight loss because of reducing the calorie intake can lead to exhaustion. Comparing oneself with others and going for self-dieting may lead to starvation. People think that skipping a meal saves calories but end up with health problems.

In boxing and wrestling the players tend to lose weight sharply because they want to compete in lower weight category than their actual weight. A few weeks before the competition, they undergo vigorous training programme along with diet control. They wear weight jacket and go for long, run. Along with this they reduce the intake of proteins and fats in their diet. This reduces their weight instantly or sharply. The pitfalls are: 

(a) Sudden weight gain: Weight loss through exercises is a good thing but weight loss through dieting is very harmful. It makes your physique worse because after dieting when you came to your original eating pattern your body starts gaining more fat than it used to before dieting. 

(b) Dietary deficiency: When you cut short your diet, some of the major nutrients such as carbohydrates and proteins do not meet the required amount. This can lead to many deficiencies e.g.,where are dark circles under eyes and the person looks pale. Then he must go for anaemia check-up, etc. as these are the side effects of dieting. 

(c) Health Problem: Sudden weight loss because of reduced calorie intake can lead to exhaustion. It has its negative effects. People think that skipping a meal saves calories but end up with health problems.

Nutritive components of diet are proteins, carbohydrates, fats, vitamins and minerals. All these nutrients constitute a balanced diet of a person. They are also called primary components of diet.

Elements of a Balanced diet: There are many nutrients in the food but these are mainly grouped into six classes namely carbohydrates, proteins, fats, vitamins, minerals and water. The energy value of food is measured in heat units called calorie. The diet that we require is- 57% carbohydrates,30% fats and 13% proteins. Carbohydrates; Proteins and Fats to supply us energy. 

The energy yield per gram is as follows: 

(a) Carbohydrate- calories 

(b) Fat-9 calories 

(c) Protein-4 calories 

Basic elements of our diet are: 

(a) Carbohydrates: Our main source of energy comes from carbohydrates. 

(b) Proteins: They provide essential growth and repair of muscles and other body tissues. 

(c) Fats: These are a source of energy which is important in relation to fat-soluble Vitamins. 

(d) Vitamins: These are required in our body in very small amount for various metabolic process. They are divided into two groups-fat soluble and water soluble vitamins.

(e) Minerals: These contain essential elements needed as our body in small quantities. For proper growth and functioning. 

(f) Water: Water is essential for normal body functioning. It serves as a vehicle for carrying other nutrients.

Balanced Diet: It is defined as a diet which contains different types of food in such a quantity and proportions that the need for calories, amino acids. vitamins, minerals, fats, carbohydrates and other nutrients is adequately met for maintaining health. Vitality, general well-being and making a small provision for extra nutrients to withstand short duration of leanness are also needed in a balanced diet. 

Functions of Balanced diet: 

(a) It provides energy for the various activities of the body. 

(b) It helps the body to grow and replace wornout tissues. 

(c) It has the chemicals, which help to control the body functions and protect the body from diseases.

Various food myths are:

(a) Low fat foods are always better for you: Without fat, the human body is unable to absorb a large percentage of the nutrients needed to survive. Additionally, fat deprivation prevents messages from being passed between neurotransmitters, resulting in all kinds of neural misfiring in the body; While good fat and bad fat do exist, the right fats in the proper amounts can actually aid in weight loss and cholesterol management. 

(b) Dairy is the only thing for healthy bones: Dairy contains calcium, but so do dark green leafy vegetables. Additionally, bone health goes beyond calcium and vitamin D. Vitamin K is important for bone health. Magnesium also plays an important role in bone health. There should be enough calcium in your diet and while milk and cheese are good sources of it, they are by no means the only sources. 

(c) Eating eggs will jack up your cholesterol: More often than not, a person diagnosed with high cholesterol will go out of his way to avoid eggs. which is really unnecessary. The body's cholesterol levels are influenced by certain saturated and trans-fats. Depriving yourself of an egg means foregoing vitamins and minerals because egg is called a complete food with all nutrients in it. 

(d) Having kesar (saffron) during pregnancy makes your baby fair: Even though milk and saffron are good for you. but it is not going to help your baby becoming fairer. The skin colour of the body depends solely on the parents' genes. 

(e) The skin of an apple contains no nutrients: The apple peel in fact, is known to have a higher concentration of antioxidants. Nowadays the apples available in the market are polished with-wax to make the look shiny and glossy. So, wash it properly before biting into it. 

(f) Eating after 7 p.m. will make you fat: Expert says that it is not when you eat that makes you fat. Actually what you eat and the amount of calories you intake makes you fat.

(g) Having milk immediately after eating fish: Some believe that this combination makes you sick, or makes white spots appear on your skin. There are a few combinations of food items which ma\i cause skin allergies. They should be avoided and experts guidance taken. 

(h) Papaya should be avoided during pregnancies: This one is extremely common in India. Papaya has been known to trigger uterine contractions. A completely riped papaya is rich in vitamin and minerals which are actually beneficial for pregnant women. Consult your doctor. 

(i) Having chocolate causes acne: Most teenagers and parents believe it. However, there is no scientific reason to prove this. Experts maintain that different foods may cause skin to break into pimples.