Hi vinod i got a physics solution for a maths question,

find the y co-ordinate center of mass (COM) of the region of curve bounded by X=1 and X=0 ......................... u will get as (1/4).

Now ,
volume = 2*(y co-ordinate) =  / 2

Its bcos the curve is rotated about X axis and distance between X axis and COM is y co- ordinate.

 

If curve is rotated about Y axis V = 2* (x co-ordinate)