A body of mass 6 kg at rest is acted upon by a force. Its velocity changes to 5 m s^–1. Find its initial and final momentum (in kg m s⁻¹).

Given Mass, m = 6 kg

Initial velocity, u = 0 m s⁻¹

Final velocity, v = 5 m s⁻¹

Initial momentum (p1)

Since the body is at rest, its initial momentum is zero.

(∴ p = mass × velocity) p₁ = 0

∴ Final momentum, (p₂) = mv

p₂ = (6 kg) × (5 m s⁻¹) = 30 kg m s⁻¹