Work, power, and energy

What are the two necessary conditions for work to be done?

• Force and Velocity

• Force and Displacement

• Force and Time

Which of the following illustration shows elastic potential energy?

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• 
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A soccer player kicks a ball with 20 Newtons of force causing it to travel 100 meters. How much work is done on the ball?

• 200 J

• 80 J

• 5 J

• 2000 J

How much work is done in holding a 15 N sack of potatoes while waiting in line at the grocery store for 3 minutes?

• 15 J
• 45 J
• 0 J
• 5 J

Which situation is work not done?

• lifting a 20 pound box off the floor
• holding a 20 pound box above the floor
• sliding a 20 pound box across the floor
• sliding a 20 pound box up an inclined plane

If 150 Joules of work is needed to move a box 10 meters, what force was used? 

• 1500 N
• 15 N
• 1.5 N
• 150 N

At which point(s) on the roller coaster is the gravitational potential energy at its maximum?

• A
• B
• C
• D

If a marble had a mass of 0.30 kg and the hill was 2.3 m tall, how much potential energy did it have at the top of the hill?

• 2.3 J

• 0.23 J

• 6.9 J

• 5.2 J

Explain what happens to the potential energy of a rock as it falls off the side of a cliff.

• The kinetic energy decreases as the potential energy increases.
• The kinetic energy decreases as the potential energy decreases.
• The potential energy decreases as the kinetic energy increases.
• The potential energy decreases as the kinetic energy decreases. 

Lilly's cat ran through your yard. The cat has a mass of 5.00 kg. He is running at a speed of 3.00 m/s. What is the kinetic energy of the cat as he runs?

• 8.5 J

• 45.0 J

• 7.50 J

• 22.5 J