Question 1

A weight lifter lifts a 340 N set of weights from ground level to a position over his head, a vertical distance of 2.20 m. How much work does the weight lifter do, assuming he moves the weights at constant speed? J

Question 2

A horizontal force of 150 N is used to push a 33.5 kg packing crate at a distance of 5.10 m on a rough horizontal surface. If the crate moves at a constant speed, find each of the following.

(a) the work done by the 150 N force J (b) the coefficient of kinetic friction between the crate and the surface

Question 3

A sledge loaded with bricks has a total mass of 18.0 kg and is pulled at constant speed by a rope inclined at 21.0 above the horizontal. The sledge moves a distance of 20.8 m on a horizontal surface. The coefficient of kinetic friction between the sledge and surface is 0.500.

(a) What is the tension in the rope? N (b) How much work is done by the rope on the sledge? kJ (c) What is the mechanical energy lost due to friction? kJ

Question 4

A 7.0 kg bowling ball moves at 2.05 m/s. How fast must a 3.00 g Ping-Pong ball move so that the two balls have the same kinetic energy? m/s

Question 5

A mechanic pushes a2.4010³kg car from rest to a speed ofv, doing4750J of work in the process. During this time, the car moves27.0m. Neglecting friction between car and road, find each of the following.

(a) the speed v m/s (b) the horizontal force exerted on the car N

Question 6

A projectile is launched with a speed of 43 m/s at an angle of 58 above the horizontal. Use conservation of energy to find the maximum height reached by the projectile during its flight. m