A 1000kg car is moving at 10m/s. A 400N force is on the car for 5 seconds. What is the change in momentum of the car.

From Newton's second law of motion,

F = m*a

= m * (change in velocity) / time [As a = (change in velocity) / time]

From the question, we know

F = 400 N, time = 5 s

Therefore,

400 = 1000 * (change in velocity) / 5

i. e. change in velocity = 2 m/s

Momentum = m * velocity

Therefore,

Change in momentum = (change in mass) * (change in velocity)

= 1 * (change in velocity) [As m remains the same]

= 1 * 2

= 2 kgm/s