physics problem

acc. of platform = - 32 Ï€² cos(4Ï€t)
=> pseudo force on sphere = 32 Ï€² cos(4Ï€t)
force eqn. of sphere => 32 Ï€² cos(4Ï€t) - f = ma
torque eqn. => f.R = 2/5 mR^2 α
a = Rα
solving gives tht answer

what's the answer?

- 32/3 Ï€² cos(4Ï€t)

what is wrong in my soln. ?

MI of a cylinder =MR²/2

Does that give correct answer.Don't know wherefrom I'm getting an extra 2 in numerator

Hi all, get relevant and useful flash animations in physics at http://www.mksfoundation.com/flashlets.aspx
and lot of other free stuff for JEE preparation at this site.