Question

What conditions are needed for static friction to come into play?

Answer 1

For static friction to come into play,

- there should be a force acting on the body so that it would create a impending motion.
- the magnitude of the force should be less than the maximum value of static friction.

Answer 2

1)The given object should be at rest

being in contact with each other.

2)There should be interlocking of irregularities on the surface in contact.

3)A force should act on one of the objects and tried to move.

4)Still object should remain at rest relative to another surface on object in contact.

Then static friction comes to play to hold the contacting object placed related to each other. Hence the static friction is developed equal to the applied force