* A round object of mass (m) and radius (R) is rolling down on inclined plane without slipping.
* There are two force acting on the object along the inclined plane.
* One is the component of gravitational force (mg sinΦ) and the other is the static friction force (f).
* The other component of gravitational force (mg cosΦ) is cancelled by the normal force (N) exerted by the plane.
* The free body diagram (FBD) of the object.

mg sinΦ is the supporting force and f is the opposite force.
mg sinΦ-f=ma...(1)
The mg sinΦ cannot torque as it passes through it but the frictional force f can set torque of Rf
Rf=Iα
By using the relation a=rα,and moment of inertia I=mk2,we get
Rf=mk2a/R;
f=ma[k2/R2]
Now equ (1) becomes
mg sinΦ=ma[K2/R2]=ma
mg sinΦ=ma+ma[k2/M2]
a[1+K2/R2]=g sinΦ
After rewriting it for acceleration we ge
a=gsinΦ/[1+K2/R2]