Question

A 5 kg box on a horizontal table is pushed by a horizontal force of 15 N as shown

below. If the coefficient of friction is 0.4, will the box move?

Answer 1

Find the force required to move the box. This force must be greater than force of friction $f$:

$$f=\mu mg=0.4·5·9.8=21.6\text{ N}.$$

The box will not move.