Review of Work, Power, and Energy

A ball is thrown straight up in the air. When the ball reaches its highest point, which of the following is true?

• It has maximum kinetic energy 
• It has zero acceleration
• It has maximum gravitational potential energy 
• It has maximum elastic potential energy 

A 0.50 kg ball swings freely back and forth in an arc from point I to point IV, as shown. Point I is 1 m above Point II. Point II is the lowest point in the path. The speed of the ball at point II is most nearly

• 3.0 m/s
• 4.4 m/s
• 9.8 m/s
• 20 m/s

The kinetic energy of a car is 8 x 10⁶ J as it travels along a horizontal road. How much power is required to stop the car in 10 s? 

• 0 W
• 80,000 W
• 800, 000 W
• 8 W

The force as a function of displacement if a moving object is presented in the graph. How much work is done when the object moves from 0 m to 5 m? 

• 30 J
• 12.5 J 
• 7.5 J
• 25 J 

Which of the following statements about the objects in the picture is true? 
I. Object I has a greater potential energy 
II. Object II has a greater potential energy 
II. The two objects have the same potential energy. 

• I
• II
• III
• I  and II 

A 4 kg block is attached to a vertical spring with a spring constant of 800 N/m. The spring stretches 5 cm. How much elastic potential energy is stored in the system? 

• 1.0 J 
• 0.5 J
• 1.5 J 
• 800 J 

A spring is stretched by a force and it is plotted vs. displacement. How much elastic potential energy is stored in the spring when it is stretched 10 cm? 

• 0.1 J
• 0.2 J 
• 0.5 J 
• 0.3 J

A roller coaster completes the following course. If the roller coaster car starts from rest at point A, what is the speed of the car at point C? 

• 20 m/s
• 30 m/s
• 10 m/s
• 100 m/s