Practice it) In a crash test, a car of mass 1.53 103 kg collides with a wall and rebounds as shown in the figure. The initial and final velocities of the car are vi = -14.7 m/s and vf = 2.65 m/s, respectively. If the collision lasts for 0.142 s, find (a) the impulse delivered to the car due to the collision and (b) the size of and direction ('+' or '−') of the average force exerted on the car.