A solid body is balanced on a lever by a fixed weight, about a fulcrum, with the distance be fulcrum and the weight being 50 units. When the body is completely immersed in water, the distance had to be decreased by 25 units and when immersed in alcohol, the distance had to be decreased by 20 units. What is the specific gravity of alcohol?

A solid body is balanced on a lever by a fixed weight, about a fulcrum

1.	A solid body is balanced on a lever by a fixed weight, about a fulcrum, with the distance be fulcrum and the weight being 50 units. When the body is completely immersed in water, the distance had to be decreased by 25 units and when immersed in alcohol, the distance had to be decreased by 20 units. What is the specific gravity of alcohol?
Answer» Solution :Let/unit be the distance of the body from the fulcrum. Let m.m, and m, be the mass of the body in air, water and alcohol respectively and the fixed weight. Applying principle of moments to each of the THREE cases we have mg,=50W …….(i) `m_(1)GL`=25W .........(ii) and `m_(2)gl=30W` ..........(III) SUBTRACTING (ii) and (iii) separately from we have `(m-m_(1))gl`=25W.......(iv) and `(m-m_(2))`gl=20W .......(iv) R.D of alcohol =`("Mass of certain volumw of alcohol")/("mass of the same volume of water")=(m-m_(2))/(m-m_(1))` DIVIDING equation (v)by equation (iv) `(m-m_(2))/(m-m_(1))=(20)/(25)=0.8`