Question

A rod AB of weight $W_1$ is placed over a sphere of weight $W_2$ as shown in the figure. If friction is absent, the number of forces to be shown on the sphere in its FBD is/are?

• A. 3
• B. 4
• C. 5
• D. 6

Answer 1

The correct option is B 4


FBD of the Sphere: All contact surfaces are tangential. Hence, the normal reaction at each contact passes through the center of the sphere.
FBD of the rod: , we can see that $N_2$ has horizontal component which can-not be balanced by any other force. This implies that the rod will have an unbalanced net force, and hence, an acceleration towards the right.