Question

How does the effect of force differ when it is applied on (a) a rigid body, (b) non rigid body?

Answer 1

When a force is applied on a rigid object, it does not change the interspacing between constituent particles and does not change the dimensions of the object but can cause a change in its state of rest or motion.
When a force is applied is on a non-rigid object, there can be a change in interspacing between its constituent particles, can cause a change in its dimensions, and can cause a change in its state of rest or motion.