Question

A 20 kg block rests on a rough horizontal table. A rope is attached to the block and is pulled with a force of 80 N to the left. As a result, the block accelerates at 2.5 m/s2. What is the coefficient of kinetic friction between the block and the table?

Answer 1

Explanation:

Fnet = ma = (20kg)(2.5m/s²) = 50N to the left.

Hence Ff = 30N to the right. (Ff is frictional force)

Coefficient of kinetic friction

= Ff / Normal force

= 30N / (mg)

= 30N / [(20kg)(9.81N/kg)]

= 0.15.