1. A 0.50 kg laboratory dynamics cart with an initial velocity of 3.0 m/s [right] accelerates for 2.0 s at 1.2 m/s [right] when pulled by a string. Assume there is no friction acting on the cart. (a) Calculate the force exerted by the string on the cart. (b) Calculate the displacement of the cart. (c) Calculate the mechanical work done by the string on the cart.

2. (a) Describe a situation in which pushing a wheelbarrow filled with soil does no work. (b) Describe two different situations in which pushing a wheelbarrow full of soil does work.

3. A 2100 kg car starts from rest and accelerates at a rate of 2.6 m/s for 4.0s. Assume that the force acting to accelerate the car is acting in the same direction as its motion. How much work has the car done?

4. A roller coaster drops from the initial high point and continues to rise and fall as it follows the track up and down. Explain how transformations between kinetic and potential energy are related to the rising and falling of the roller coaster.

5. A 1900 kg car slows down from a speed of 25.0 m/s to a speed of 15.0 m/s in 6.25 s. How much work was done on the car?

6. A 68 kg rock climber who is a bungee jumper has a mass of 73 kg and falls a distance of 120 m before the bungee catches and sends the jumper upward. Use the law of conservation of energy to calculate the speed of the jumper just before the bungee catches.

7. A mountain climber with a mass of 55 kg starts from a height of 850 m above the sea level at 9 in the morning and reaches a height of 2400 m by noon. What is the climber's average power?

8. A 60.0 kg person accelerates from rest to 12 m/s in 6.0 s. What is the person's power?

9. Suppose a bicycle and its rider has a mass of 75kg. The bicyclist does 4700J of work to travel 210m along a road whose slope increases to an angle of 1.5 with the horizontal. Calculate the efficiency of the bicycle.

10. How much heat is given off when 300.0 g of water at 0C freezes at 0C?

11. Someone pours 150.0 g heated lead shot into a 250.0 g aluminum calorimeter cup that contains 200.0 g of water at 25C. The final temperature is 28C. What was the initial temperature of the lead shot?

12. How much heat is required to: (a) Convert 50.0 g of water at 100C to steam at 100C? (b) Change 100.0 g of ice at -10C to steam 130C?