3rd Law, Potential vs Kinetic Energy, Transformation of Energy Review

1. The diagram shows a girl pulling a wagon with a force of 30 N. What is the force with which the wagon pulls the girl?

• 10 N
• 20 N
• 30 N
• The wagon does not pull the girl

2. Which of the following BEST explains why Alex is able to move backward on the swing when he pushes his feet forward and against the ground?

• When Alex pushes his feet against the ground, his body bends backward.
• When Alex pushes his feet against the ground, the ground pushes him back with an equal and opposite force
• When Alex pushes his feet against the ground, the wind pushes him backward.
• When Alex pushes his feet against the ground, the swing pushes him forward.

3. The picture illustrates four different situations of force. Which illustration is an example of Newton’s Third Law of motion?

• Book lying on a table
• A balloon suspended in air
• A model rocket at rest
• A hurdler jumping over a hurdle

4. During an investigation to compare potential and kinetic energy, a student wrote the following statements. Which statement about potential and kinetic energy is NOT correct?

• Both potential and kinetic energy can be converted to other forms of energy.
• A rock on top of a hill has potential energy. A stretched rubber band on the slingshot has kinetic energy.
• Potential energy is the energy stored in an object due to its position. Kinetic energy is the energy that an object has because of its motion.
• Potential energy of a raised object depends on the mass of the object and its height above the ground. Kinetic energy depends on the mass of the object and its speed.

5. Which of the divers in this picture has the least gravitational potential energy?

• P
• Q
• R
• S

6. In which of the positions shown in the picture will Joshua have both potential energy and kinetic energy?

• P and Q
• P and R
• Only Q
• Only R

7. According to law of conservation of energy, energy can be ___________?

• Created
• Destroyed
• Created or destroyed
• Transformed from one form to another

8. According to the Law of Conservation of energy, the amount of energy before and after a bumper car collision must be the same. Which statement below is true?

• The total energy is conserved.
• The total energy is more after the collision.
• The total energy is less after the collision.
• The mass of the cars is needed to determine the energy.

9. What is the ultimate ORIGINAL source of energy in a food web?

• Producers
• Primary consumers
• The sun
• Secondary consumers

10. The diagram shows a simple roller coaster track. At which point on the track is the gravitational potential energy of the coaster car the highest?

• A
• B
• C
• D