A 300 g hockey puck is shot across an ice-covered pond. Before the hockey puck was hit, the puck was at rest. After the hit, the puck has a speed of 40 m/s. The puck comes to rest after going a distance of 30 m. (a) Describe how the energy of the puck changes over time, giving the numerical values of any work or energy involved. (b) Find the magnitude of the net friction force.

A large cruise ship of mass 6.00 ✕ 107 kg has a speed of 12.4 m/s at some instant. (a) What is the ship's kinetic energy at this time?                           J(b) How much work is required to stop it? (Give the work done on the ship. Include the sign of the value in your answer.)                                                 J(c) What is the magnitude of the constant force required to stop it as it undergoes a displacement of 3.40 km?                             N

A 1.50-kg block at rest on a ramp of height h. When the block is released, it slides without friction to the bottom of the ramp, and then continues across a surface that is frictionless except for a rough patch of width 10.0 cm that has a coefficient of kinetic friction µk = 0.60. Using conservation of energy, find h such that the block’s speed after crossing the rough patch is 3.50 m/s.

A 5.40-kg block is set into motion up an inclined plane with an initial speed of v; = 8.20 m/s (see figure below). The block comes to rest after traveling d = 3.00 m along the plane, which is inclined at an angle of 0 = 30.0° to the horizontal. (a) For this motion, determine the change in the block's kinetic energy. J (b) For this motion, determine the change in potential energy of the block-Earth system. J (c) Determine the friction force exerted on the block (assumed to be constant). N (d) What is the coefficient of kinetic friction?