Question

A constant retarding force of 50 N is applied to a body of mass 20 kg moving initially with a speed of 15 ms^–1. How long does the body take to stop?

Answer 1

Retarding force, F = –50 N
Mass of the body, m = 20 kg
Initial velocity of the body, u = 15 m/s
Final velocity of the body, v = 0
Using Newton’s second law of motion, the acceleration (a) produced in the body can be calculated as:

Using the first equation of motion, the time (t) taken by the body to come to rest can be calculated as: v = u + at