Q.

A force of 49 N acts tangentially at the highest point of a sphere (solid) of mass 20 kg, kept on a rough horizontal plane. If the sphere rolls without slipping, then the acceleration of the center of the sphere is        [2025]

1 3.5 m/s2  
2 0.35 m/s2  
3 2.5 m/s2  
4 0.25 m/s2  

Ans.

(1)

Torque about bottom point, F×2r=Iα

49×2r=75mr2α

14=4rα          ... (i)

As sphere rolls without slipping

a=rα          ... (ii)

 a=144=72=3.5 m/s2