1) A 55 kg skier is at the top of a slope, as in the figure. At the initial point A, the skier is 11.1 m vertically above the final point B. The acceleration of gravity is 9.81 m/s 2. a) Find the difference in gravitational potential energy associated with the skier at the points A and B if the zero level for gravitational potential energy is at point B. Answer in units of J

B) Find the difference in potential energy if the zero level is midway down the slope, at a height of 5.55 m. Answer in units of J.

2) A 0.9 kg rock slides horizontally off a table from a height of 1.5 m. The speed of the rock as it leaves the thrower's hand at the edge of the table is 1.4 m/s, as shown. The acceleration of gravity is 9.81 m/s 2 . How much time does it take the rock to travel from the edge of the table to the floor? Answer in units of s.

b) What is the kinetic energy of the rock just before it hits the floor? Answer in units of J.

3) A 17.1 kg block is dragged over a rough, horizontal surface by a constant force of 89.1 N acting at an angle of 34 above the horizontal. The block is displaced 93.8 m, and the coefficient of kinetic friction is 0.104. The acceleration of gravity is 9.8 m/s 2. Find the work done by the 89.1 N force. Answer in units of J.

B) Find the work done by the force of friction. Answer in units of J.

C) If the block was originally at rest, determine its final speed. Answer in units of m/s

4) A 17.1 kg block is dragged over a rough, horizontal surface by a constant force of 89.1 N acting at an angle of 29 above the horizontal. The block is displaced 93.8 m, and the coefficient of kinetic friction is 0.104. The acceleration of gravity is 9.8 m/s 2 . If the block was originally at rest, determine its final speed. Answer in units of m/s.

5) Water flows over a section of Niagara Falls at the rate of 1.2 106 kg/s and falls 49.6 m. The acceleration of gravity if 9.81 m/s 2 . How much power is generated by the falling water? Answer in units of W.

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