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The motor of an electric train can give it an acceleration of 1 m/s^2 and brakes can give it retardation of 3m/s^2. Find the shortest time in which train can make a trio between two stations 1215 m apart.

A particle is projected with a speed $V$ from a point O making an angle of ${30}^{\circ }$ with the vertical. At the same instant, a second particle is thrown vertically upwards with a speed $v$ from a point A. The two particles reach $H$, the highest point of the parabolic path of particle one simultaneously. Then ratio $V/v$ is

What is inert electrode

In the figure shown below, a horizontal force $F$ is applied on $6kg$ block towards left. If the coefficients of friction between the surfaces are $0.3$ and $0.4$ as shown in the figure. then the value of tension in the rope and force required just to slide the $6kg$ block under the $3kg$ block is (Take $g=10m/s^2$)

A long wire carrying current $i$ has been bent into the shape as shown in figure. $AB$ and $CD$ are circular arcs centred at $O$, having radius $2r$ and $3r$ respectively. $EF$ is a semicircle of radius $r$ centred at $O$, all other segments are straight and radial pointing towards $O$. Find the magnetic field at the point $O$.

A particle is released from a certain height H=400m. Due to wind it gathers a horizontal velocity component v_x=ay where a=√5 s^-1 and y is the verticle displacement of particle from the point of release, then find

A) the horizontal drift of particle when it hits the ground.

B) the speed with which particle strikes the ground (g=10m/s²)

Check the correctness

$s=u+\frac{1}{2}a(2t-1)$

What is the equivalent resistance across A and B in the figure if R = 3Ω?

The angle of incidence at which, reflected ray is totally polarised for reflection from air to glass (refractive index $=n$) is:

Which of the following equation does not represent a simple harmonic motion

A stone is allowed to fall from the top of a tower $100\text{m}$ high and at the same time, another stone is projected vertically upwards from the ground with a velocity of $25{\text{ms}}^{-1}$. The two stones will meet after

One mole of a monoatomic ideal gas is taken along two cyclic processes $E\to F\to G\to E$ and $E\to F\to H\to E$ as shown on given $P-V$ diagram.
The processes involved are purely isochoric, isobaric, isothermal or adiabatic.

Which of the following is/are correct ?

Find the speed of uniform solid sphere after rolling down (without sliding) an inclined plane of vertical height $h=0.14\text{m}$ from rest is (Take $g=9.8{\text{m/s}}^2$)

A source emits 31.4 W of radiant flux distributed uniformly in all directions. The luminous efficiency is 60 lumen $wat{t}^{-}1$ . What is the luminous intensity of the source ?

A solid cylinder of mass m = 4 kg and radius R = 10 cm has two ropes wrapped around it, one near each end. The cylinder is held horizontally by fixing the two free ends of the cords to the hooks on the ceiling such that both the cords are exactly vertical. The cylinder is released to fall under gravity. Find the tension in the cords when they unwind and the linear acceleration of the cylinder.

Angle between tangents from directrix to the parabola is

A hollow nonconducting sphere of radius "R "with charge "q" uniformly distributed over its surface. The sphere starts rotating with a constant angular velocity "w".about an axis passing through the centre of sphere.the net magnetic field at the centre of the sphere is..?

1.uqw÷2pi R

2.uqw÷3 pi R

3.uqw÷8 pi R

I don't know that how to know whether the question belongs to vector dot product or vector cross product...

A soap film has been developed over a wire loop. If surface tension of the soap solution is $0.015\text{N/m}$, find the tension in the thread loop of length $12.56\text{cm}$ which is kept over the soap film, when the soap film inside it is pricked.

A rod $AB$ is shown in figure. End $A$ of the rod is fixed on the ground. Block is moving with velocity $\sqrt{3}\text{m/s}$ towards right. The velocity of end $B$ of rod when rod makes an angle of ${60}^{\circ }$ with the ground is

Carbon disulfide (n = 1.63) is poured into a container made of crown glass (n = 1.52). What is the critical angle for internal reflection of a ray in the liquid when it is incident on the liquid-to-glass surface?

Coefficient of friction between two blocks is $\mu =0.6$. The blocks are given velocities in the directions shown in the figure below. Find the common velocity attained by both the blocks. [Take $g=10{\text{m/s}}^2$]

A body is executing simple harmonic motion with an angular frequency 2rad/s. The velocity of the body at 20 mm displacement, when the amplitude of motion is 60 mm, is

[CPMT 1999]

In a photoelectric experiment, the potential difference V that must be maintained between the illuminated surface and the collector so as just to prevent any electron from traching the collector is determined for different frequencies f of the incident illumination. The graph obtained is shown. The maximim kinetic energy of the electrons emitted at frequency $f_1$ is

A large number of bullets are fired in all directions with same speed u. What is the maximum area on the ground on which these bullets will spread

Ram goes from point A to B by auto at the speed of 20 km/hr and comes back from B to A in a cab at a speed of

80 km/hr. Find his average speed.

A body is moving with a uniform velocity of 10 m/s on a circular path of diameter 2.0m. calculate

1) the difference between the magnitude of the displacement of the body and the distance covered in half a round and

2) the magnitude of the changes in velocity of the body in half a round.

A thick walled hollow sphere has outer radius R. It rolls down an inclined plain Without slipping and its speed at the bottom is v. If the inclined plane is frictionless and the sphere slides down without rolling, its speed at the bottom will be 5v/4. What is radius of gyration of the sphere.

R_{​​​​​​1} = 100 ± 3

R_{​​​​​​2} = 200 ± 4

Find the resistance in series and parallel combination .

My solution :

Series connection

R_{​​​​​​S} =(100±3)+(200±4)

R_s =300±7

Parallel connection

R_{​​​​​​p} = (R_{​​​​​​1}R_{​​​​2})÷(R_​1 + R_{​​​​​​2})

R_{​​​​​​p} = {(3/100)(4/200)}÷(300±7)

R_{​​​​​​p} = (3/5000)÷(300±7)

What to do after this ???

I am not able to get it .

Please help me out .

Can centre of gravity of a body be shifted by external load??

A black body at 200 K is found to exit maximum energy at a wavelength of $14\mu m$. When its temperature is raised to 1000 K, the wavelength at which maximum energy is emitted is

The angular speed of the hour hand of a watch is :

Three blocks A, B and C weighing 1, 8 and 27 kg respectively are connected as shown in the figure with an in extensible string and are moving on a smooth surface. $T_3$ is equal to 36 N. Then $T_2$ is

In an experiment, brass and steel wires of length $1\text{m}$ each with areas of cross-section $1{\text{mm}}^2$ are used. The wires are connected in series and one end of the combined wire is connected to a rigid support and other end is subjected to elongation. The stress requires to produce a net elongation of $0.2\text{mm}$ is
[Take Young’s modulus for steel and brass as $120\times {10}^9{\text{N/m}}^2$ and $60\times {10}^9{\text{N/m}}^2$respectively]

The intensity ratio of two waves is 1 : 16. The ratio of their amplitudes is

[EAMCET 1983]

Find the change in the volume of 1.0 litre kerosene when it is subjected to an extra pressure of $2.0\times {10}^{5}N{m}^{-2}$ from the following data. Density of kerosene $=800kg{m}^{-3}$ and speed of sound in kerosene = $1330m{s}^{-1}$.

The surface density (mass/area) of a circular disc of radius a depends on the distance from the centre as p(r)= A + Br. Find its moment of inertia about the line perpendicular to the plane of the disc through its centre.

If $y=cos\left(3co{s}^{-1}x\right)$, then $\frac{d^{2}y}{d{x}^2}$