A plank with a uniform sphere placed on it rests on a smooth horizontal plane. Plank is pulled to right by a constant force F. If sphere does not slip over the plank. Which of the following is correct.

Question

G1 Physics · Accepted Answer

For the sphere, static friction is the only horizontal force doing work, so its work equals the increase in the sphere’s total kinetic energy; statement B is true. No slip on the accelerating plank requires aCM-aplank=αR, which gives aCM<aplank, so A is true. For the whole sphere+plank system on a smooth ground, the only external horizontal work is done by F, hence ΔKtotal=WF and C is true. Therefore A,B,C are correct.