12. A squirrel standing on a branch rolls an acorn toward a hole in the tree. To determine how the potential energy of the acorn changes in relation to the earth, the position of what two objects must be considered?

Question

A) The position of the squirrel on the branch and the earth
B) The height of the branch and the position of the acorn
C) The position of the acorn and the earth
D) The position of the acorn and the width of the hole in the tree

13. Ellen drops a ball from a cliff. Which statement best describes the ball's energy as it falls from her hand?

a
The ball's kinetic energy decreases while its potential energy increases.
b
The ball's kinetic energy increases but its potential energy remains the same.
c
The ball's potential energy decreases while its kinetic energy increases.
d
The ball's potential energy is changed to thermal energy.

15. Mrs. Wilson is driving her car to the store. She drives on a street where the speed limit is 50 mph. Then she turns onto a street where the speed limit is 45 mph. What happens to the kinetic energy of her car?
A) When she slows from 50 mph to 45 mph, the car’s kinetic energy stays the same.
B) When she speeds up from 45 mph to 50 mph, the car’s kinetic energy is changed to potential energy.
C) When she slows from 45 mph to 50 mph, the car’s kinetic energy decreases.
D) When she slows from 50 mph to 45 mph, the car’s kinetic energy increases.

16. Which object has kinetic energy?

a
a bird perched in a tree
b
a person standing at the top of stairs
c
a ball sitting under a table
d
a person running on the sidewalk

17. Which object has potential energy?

a
a person walking down the street
b
a soccer ball rolling across a field
c
a car moving down the interstate
d
an acorn sitting on top of a roof

Answer 1

Here are the answers to your questions:

12. The potential energy of the acorn changes in relation to the earth based on its height relative to the earth. Therefore, the correct answer is: C) The position of the acorn and the earth

13. As Ellen drops the ball from a cliff, its potential energy decreases as it falls and converts into kinetic energy. Thus, the best statement is: c) The ball's potential energy decreases while its kinetic energy increases.

15. When Mrs. Wilson slows down from 50 mph to 45 mph, her car’s speed decreases and so does its kinetic energy. Therefore, the correct answer is: C) When she slows from 50 mph to 45 mph, the car’s kinetic energy decreases.

16. The object that has kinetic energy is the one that is in motion. Hence, the correct answer is: d) a person running on the sidewalk

17. The object with potential energy is one that is positioned to potentially do work due to its position. Therefore, the correct answer is: d) an acorn sitting on top of a roof

This acorn has potential energy due to its height above the ground.