I am also getting the same answer.
Akash Anand Excellent work ..
Upvote·0· Reply ·2014-03-01 04:14:22
a) 12mv02 = 12kx2, x = Rθ
b) 12mv02 = 12kx2 + 12mv2, x = RÏ€4
atotal = √[(v2R)2 + (kxm)2]
θmax=π2.
Magnitude of acceleration at θ=π4 is 25√(916+1π2).
I am also getting the same answer.