A hollow smooth uniform sphere  A of mass m rolls without sliding on a smooth horizontal surface . It collides elestically and head on with another stationary smooth solid sphere B of the same mass m and same radius . the ratio of the kinetic energy of  B to that of A just after the collison is.........?

a) 5:2

b) 2:3

c)3:2

i should say that this q is really verrrrry good. it tests ur fundamentals......i will put my views about the problem i don't know why any one never thaught of what i thaught of when i read the q ......see in any such problem first analyse what happens...there is a sphere rolling on a smooth surface and the surface of the sphere is also smooth.....do u get it now......how will the 2nd sphere ever start rolling????????????...........if there in no friction between the surfaces of the sphere............even if u assume ( which is definately wrong) that the second shhere will get some ang vel some how........ how will it start pure rolling?????????????if  the surface is smooth......the second sphere will slide without rolling with some vel....now it is simple to calc...

oh dis is from one of the testpapers of my class........