Two bodies of mass m and 4m are attached to a string as shown in the figure. The body of mass m hanging from string is executing oscillation with angular amplitude 60° while other body is at rest on a horizontal surface. The minimum coefficient of friction between the mass 4m and the horizontal surface is :

Question

G1 Physics · Accepted Answer

The oscillating bob produces the largest horizontal pull on the 4m block at the critical position. Using energy for the bob and resolving string tension gives the required limiting friction µ(4mg)=2mg, hence µ=1/2. Therefore C.