Q1: The force acting on a point on the surface of a rigid body may be considered to act

ANS:C - on any point on the line of action of the force

1. Center of Gravity: The force acting on a rigid body doesn't necessarily have to be applied at the center of gravity. In many cases, forces are applied away from the center of gravity.
2. On the Periphery of the Body: While forces can indeed be applied at any point on the body's surface, they are not restricted to the periphery. Forces can be applied anywhere on the body's surface.
3. On Any Point on the Line of Action of the Force: This statement is true. When considering the effects of a force on a rigid body, it is convenient to think of the force as acting at any point along the line of action of the force. This is particularly helpful when dealing with torque or rotational effects.
4. At Any Point on the Surface Normal to the Line of Action of the Force: This statement is not always true. While it's correct that forces normal to the surface can exist, they might not be directly related to the line of action of the force in question. Forces normal to the surface may be due to different interactions.