Question

pls help me to answer this...​

Answer 1

Answer:

1. As in this question, in figure c) box just begin to slide when force applied is 3F. Hence, its limiting friction is 3F. B) An object in rest does not move or slide unless the force applied on it is more than limiting friction.
2. B) An object in rest does not move or slide unless the force applied on it is more than limiting friction. As in figures a and b, the applied force is less than limiting friction, ie, 3F, therefore the box remains at rest.
3. Friction came into play when it irregularities have been present in the surface of two objects. It the direction is in opposite to the motion, the body aligned to the center and hence frictional force is always directed in the opposite direction. Therefore, lesser force is required to overcome interlocking.