1) An elevator accelerates at a constant rate from an initial downward velocity of 10.0 m/s to a stop in 2.00 s. A passenger in the elevator is holding a 3.00 kg package by a vertical string. What is the tension in the string during the process?

2) Two blocks, one on top of the other slide together down a frictionless plane inclined at 37 degrees. The mass of the top block is 25.0 kg, and the mass of the lower block is 30.0 kg. What is the magnitude of the acceleration of the two-block system? Assume there is no friction between the blocks and the two blocks move together without the top block slipping with respect to the bottom one.

3) A 10.0 kg block sits on a plane inclined at 143 degrees. What must be the frictional force between the block and the inclined plane if the block is not to slide when the inclined plane is accelerating to the right at 3.00 m/s2?

4) Suppose a 0.006 kg bullet traveling at 100.0 m/s strikes a bulletproof vest and comes to rest in about 0.005 s. What average force does the bullet exert on the vest while coming to a stop?

5) A car traveling at 10.0 m/s is involved in a head-on crash. The driver, whose mass is 60.0 kg, is to be brought to rest within the passenger compartment by uniformly compressing an inflated air bag through a distance of 0.30 m. Find the average force exerted on the air bag by the driver during the collision.

6) A person pushes a shopping cart with a force of 100 N acting down at 45 degrees. The mass of the cart is 10.0 kg. The cart travels rightward at a constant speed of 1.30 m/s. Ignore the effect of air resistance. What is the magnitude of the friction force acting horizontally on the cart? What is the magnitude of the normal force on the cart exerted by the ground?

7) A 2000 kg car in neutral at the top of a 20 degree inclined driveway 20.0 m long slips its parking brake and rolls down the driveway. Assume that the friction in the axles is negligible. Ignore that the wheels are turning. Find the magnitude of its velocity the instant before it hits the garage door.

8) A person of mass 100 kg is standing on top of a cliff with only an old rope that he knows will support no more than 500 N. His plan is to slide down the rope using friction to keep him from falling too fast. At what minimum rate can he accelerate down the rope in order not to break it?