A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90km/h. its velocity is slowed down to 18 km/h in 4 seconds by an unbalanced external force.
Calculate the acceleration and change in momentum . Also calculate the magnitude of the force required.

A car of mass 1000 kg moving with a velocity of 36 km/h comes to rest in 5 seconds. What is the force exerted on the car?

An object of mass 1 kg travelling in straight line with a velocity of 10 ms^(-1) collides with it and sticks to a stationary wooden block of mass 5 kg. Then both move off together in the same straight line. Calculate the total momentum before the impact and just after the impact. Also calculate the velocity of combined object.