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

Here, M = 20 kg, F = 50 (retarding force)

As F = mg ⇒ a = F/m = -50/20 = -2.5 ms^-2

Also, v = u + at, Here u = 15 ms^-1, v = 0

⇒ 0 = 15 + (-2.5) x t ⇒ t = 6s