A 55-kg box rests on a horizontal surface. The coefficient of static friction between the box and the surface is 0.30, and the coefficient of kinetic friction is 0.20. What horizontal force must be applied to the box to cause it to start sliding along the surface

The horizontal force that must be applied to the box to cause it to start sliding along the surface is 162N

Explanation:

To start sliding the box on the surface it must overcome its static frictional force under equilibrium condition

The net force on the box is

F - fs = 0

F = fs = us N = us mg

Force = (0.3) x (55 kg) x (9.8 m/s^2) = 161.7 approximately 162 N