7th grade topic # 1 TestPhysical Sciences – Potential & Kinetic Energy

_____1. Chloe dropped a golf ball from 150 cm in class. It bounced back to 90cm. Why did the ball not return back to the 150 cm height?

A. Energy was lost while the ball fell.B. Energy was added to the ball when it hit the ground.C. Energy was transferred when the ball hit the ground.D. Energy was lost as the ball rose back up.

______2. In the diagrams above the book in which one has the MOST potential energy?

A. the book in A B. the book on B

C. the book in C D. the book in D

_____3. Which of the following has kinetic energy?A. a kite stuck in a tree B. a rolling bowling ballC. a rubber band stretched back D. a car waiting at a red light

_____4. To increase the kinetic energy of a roller coaster, a person could

A. decrease the roller coaster’s speed B. increase the friction on the roller coaster

C. increase the roller coaster’s mass D. decrease the roller coaster’s mass

A. B.

C. D.

. _____5. Unlike kinetic energy, potential energy is

A. energy of position. B. energy that is not conserved.

C. energy of motion . D. energy that’s not measurable.

The diagram below shows the path of a roller coaster cart starting from rest at point W.

The roller coaster cart rolls down the track hill past point Z.

_____6. Which of the following statements BEST describes the energy of the roller coaster cart from point W to point Z?

A. The total energy at point W is less than at point Z.

B. The total energy at point W is greater than at point Z.

C. The total energy at points W and Z can’t be calculated .

D. The total energy at points W and Z are the same.

______7. Which of the following is an example of kinetic energy being changed to potential energy?

A. A runner racing down the track. B. A race car moving around a flat track. C. A sled pulled up to the top of a hill. D. A glass setting a kitchen table.

______8. Which of the following examples of energy transfer CANNOT happen?A. A toy car rolling down a hill increases speed and then rolls to a stop.B. A bunger jumper jumps from a bridge and goes up higher with each recoil.

C. A child playing on a swing moves fastest at the bottom of the swing’s path.

D. A rock dropped from the top of a bridge increases in speed until it hits the water.

_____9. When does a rubber band, which has been shot at a wall, have the most potential energy?A. When its stretched back before shot B. When it hits the wallC. When its flying across the room D. When its lying on the floor

_____10. A girl holding a ball releases it, and the ball falls to the floor.

Which graph BEST shows the changes in potential energy and kinetic energy of the ball as it falls to the floor?

A . B.

C. D.

The diagram below represents different points in a pendulum’s swing. The arrow indicates direction of motion. Assume that the system is frictionless.

____ 11. At which position in the pendulum’s swing, is kinetic energy decreasing and potential energy increasing?

A. position 1 B. position 2 C. position 3 D. position 4

_____12. A high diver steps off a diving platform that is 15 meters above the water. If no air

resistance is present, during the fall there will be a decrease in the diver’s A. gravitational potential energy. B total mechanical energy.

C. kinetic energy. D. momentum

_____13. A ball is released from the top of an inclined plane as shown below. Ignoring friction, where will the potential energy (PE) and kinetic energy (KE) of the ball be the greatest?

A. Potential energy at J, Kinetic energy at MB. Potential Energy at K, Kinetic energy at LC. Potential energy at L, Kinetic energy at KD. Potential Energy at M, Kinetic Energy at J

_____14. An example of kinetic energy continuously being changed to potential energy and back again might be —

A. a girl swinging on a swing B. a train moving down a track C. electric charges moving in a straight path D. a plate sitting on the edge of a table

_____15. Joey throws a softball into the air. It rises, stops when it reaches its greatest height, and then falls back to the ground. At what point does kinetic energy change to potential energy?

A. when the baseball is rising B. when the baseball is fallingC. just after the baseball hits the ground D. while the baseball is stopped in the air

Short Answer

16. A student learned in science class that some types of materials can store energy when they change shape as they hit a surface. Then they transfer the energy.

The student has 3 different types of spheres and he wants to find out which one will store the most energy when it hits the floor.

Explain how can he find out?

Sample answer: The student can bounce each sphere from the same height and then see which one bounces the highest. The one that bounces the highest stored the most energy.

17. Mr. Kent is placing boxes of books on some shelves. When he needs to place the same boxes on a higher shelf, describe how the gravitational potential energy of the boxes affected?

Sample answer: The gravitational potential energy of the books would be increased as Mr. Brown places them on a higher shelf.

Extended Response:

A. In illustration B above, identify the point at which the skater’s kinetic energy begins to be changed back into potential energy.

B. When the skater’s kinetic energy is changed back into potential energy, will this amount of potential energy likely be equal to the skater’s potential energy in illustration A?

Explain why or why not?

Sample Answer:

A. Point 3

B. Yes, because it’s the same track and all variables such as height are the same.