3. To improve the safety of motorists, modern cars are built so the front end crumples upon impact 1200-kg car is travelling at a constant velocity of 8.0 m/s. It hits an immovable wall and comes to a complete stop in 0.25 s. (a) Calculate the impulse provided to the car. (b) What is the average net force exerted on the car? (c) For the same impulse, what would be the average net force exerted on the car if it had a rig bumper and frame that stopped the car in 0.040 s?