Physics hollow spherical shell is rolling without slipping or sliding down a board?

Question

A hollow spherical shell is rolling without slipping or sliding down a board that is tilted at an angle of 34.0° with respect to the horizontal. What is its acceleration?

Answer 1

ma= mg sin(A) - f
ma= mg sin(A) - u mg cos(A)
f=u mg cos(A)
or f= T/R
T=IA
A= a/R so we have f= T/R=Ia/R^2
ma= mg sin(A) - Ia/R^2 where
I= (2/3)mR^2 for a hallow sphere then
ma= mg sin(A) - (2/3)mR^2a/R^2
ma= mg sin(A) - (2/3)ma
a= g sin(A) - (2/3)a
a=g sin(A)/(1+2/3) or finally
a=(3/5)g sin(A)