Little Hudson holds the 10-kgkg barbell 0.3 mm above the floor. What is the PE of the barbell relative to the floor? How much additional work will Hudson do when he lifts the barbell to a height 0.9 mm above the floor? If Hudson then drops the barbell, what will be its KE of impact with the floor?

At a carnival, you can try to ring a bell by striking a target with a 9.10-kg hammer. In response, a 0.410- kg metal piece is sent upward toward the bell, which is 5.05 m above. Suppose that 22.0% of the hammer's kinetic energy is used to do the work of sending the metal piece upward. How fast must the hammer be moving when it strikes the target so that the bell just barely rings?

Consider the system shown below (Figure 1). The rope and pulley have negligible mass, and the pulley is frictionless. Initially the 6.00 kgkg block is moving downward and the 8.00 kgkg block is moving to the right, both with a speed of 0.600 m/sm/s. The blocks come to rest after moving 3.50 mm.  Use the work-energy theorem to calculate the coefficient of kinetic friction between the 8.00 kgkg block and the tabletop.

A 7.80 g bullet is moving at 460 m/s just before it penetrates a tree trunk to a depth of 4.9 cm (ay What the magnitude of the average frletional force (In N) that is exerted on the bullet whille moving the tree trunk? Uso work considerations to o your answer. (b) Asturing the frictional force is constant, how much time elapses between the moment the bullet enters the tree trunk and the moment it moving?

The figure shows a ball with mass m = 0.499 kg attached to the end of a thin rod with length L = 0.308 m and negligible mass. The other end of the rod is pivoted so that the ball can move in a vertical circle. The rod is held horizontally as shown and then given enough of a downward push to cause the ball to swing down and around and just reach the vertically upward position, with zero speed there. How much work is done on the ball by the gravitational force from the initial point to (a) the lowest point, (b) the highest point, and (c) the point on the right level with the initial point? If the gravitational potential energy of the ball-Earth system is taken to be zero at the initial point, what is it when the ball reaches (d) the lowest point, (e) the highest point, and (f) the point on the right level with the initial point? (a) Number (b) Number i (c) Number (d) Number (e) Number (f) Number i Units Units Units Units Units Units L

Sam's job at the amusement park is to slow down and bring to a stop the boats in the log ride. If a boat and its riders have a mass of 1200 kg and the boat drifts in at 1.3 m/s how much work does Sam do to stop it? Express your answer in joules.

You are working out on a rowing machine. Each time you pull the rowing bar (which simulates the oars) toward you, it moves a distance of 1.30 m in a time of 1.80 s. The readout on the display indicates that the average power you are producing is 88.0 W. What is the magnitude of the force that you exert on the handle?