Question
The velocity of a body of mass 5 kg changes from 20 m/s to 10 m/s. Calculate the change of momentum of the body.
[Ans : 50 kg-m/s]
Solution
Mass (m) = 5 kg
Initial velocity (u) = 20 m/s
Final velocity (v) = 10 m/s
Change of momentum = m (v – u)
= 5 (10 – 20)
= 5 × (-10) = – 50 kg-m/s
The negative sign indicates that the momentum is in the opposite direction to the motion of the body.
