Plz help Suppose one of the three students in Guided Example 7.6 stops pushing the car after 6.00 s. In this case the force exerted on the car is 305 N for the first 6.00 s and 215 N for the second 6.00 s.
(a) What is the final momentum of the car?
(b) What is the final speed of the car?

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

Anybody wanna ? (picture included? )

What do you think car designers do if the damage caused by a crash test is too severe?