Question

Ablock is on rough surface.is the maximum force applied so that the block does not move is equal to the minimum force applied to just move the block?

Answer 1

A block resting on a horizontal surface and suppose a force is applied to it and still the body is not moving then, friction force is equal to applied force cancelling it

now when we increase the force to move the block then frictional force also increases

so 

f_max= μN

N=mg

so f_max= μmg