A pendulum is held at the top of its swing. The person holding the pendulum lets go, and the pendulum is allowed to swing freely. Answer the following questions about the pendulum.
a. When the pendulum is held at the top of its swing, what type of energy does it have?
(1 point)
Responses
electrical energy
electrical energy
motion energy
motion energy
potential energy
potential energy
kinetic energy
kinetic energy
Question 2
b. As the pendulum swings freely, what is happening to its energy?(1 point)
Responses
PE converts to KE as it falls, and then KE converts to PE as it rises
PE converts to KE as it falls, and then KE converts to PE as it rises
KE converts to PE, and then total energy becomes zero
KE converts to PE, and then total energy becomes zero
KE converts to PE as it falls, and then PE converts to KE as it rises
KE converts to PE as it falls, and then PE converts to KE as it rises
PE converts to KE, and then total energy becomes zero
PE converts to KE, and then total energy becomes zero
Question 3
c. When are kinetic energy and potential energy equal in magnitude (equal in amount)?(1 point)
Responses
They are equal at every position.
They are equal at every position.
They are equal at the bottom position.
They are equal at the bottom position.
They are equal half-way between the top position and the bottom position.
They are equal half-way between the top position and the bottom position.
They are equal at the top position.
They are equal at the top position.
what are a b and c
a. The type of energy the pendulum has when held at the top of its swing is potential energy.
b. As the pendulum swings freely, its potential energy converts to kinetic energy as it falls, and then the kinetic energy converts back to potential energy as it rises.
c. Kinetic energy and potential energy are equal in magnitude at the top position of the pendulum's swing.
In one part of this unit's sample work, we tested how mass impacts kinetic energy. First, the teacher allowed one ball to roll freely down a ramp. Then, from the same height on the ramp, she allowed a ball with greater mass to roll freely down the ramp. Each ball was allowed to strike a cup at the bottom of the ramp.
a. How did mass affect the ability of each ball to move the cup?
(1 point)
Responses
The cup's motion was independent of the mass of the ball.
The cup's motion was independent of the mass of the ball.
The ball with the higher mass moved the cup a greater distance.
The ball with the higher mass moved the cup a greater distance.
The ball with the lower mass moved the cup a greater distance.
The ball with the lower mass moved the cup a greater distance.
The balls moved the cup the same distance.
The balls moved the cup the same distance.
Question 2
b. How did the mass of the ball impact the ball's kinetic energy?(1 point)
Responses
An increase in mass caused an increase in kinetic energy.
An increase in mass caused an increase in kinetic energy.
A decrease in mass caused an increase in kinetic energy.
A decrease in mass caused an increase in kinetic energy.
Mass did not impact kinetic energy.
Mass did not impact kinetic energy.
An increase in mass caused a decrease in kinetic energy.
An increase in mass caused a decrease in kinetic energy.
Question 3
c. What happened to the kinetic energy of the ball when it hit the cup?(1 point)
Responses
Some of the energy was transferred to the cup.
Some of the energy was transferred to the cup.
Overall, kinetic energy was lost.
Overall, kinetic energy was lost.
All of the kinetic energy was kept by the ball.
All of the kinetic energy was kept by the ball.
Overall, kinetic energy was gained
a b and c
a. The ball with the higher mass moved the cup a greater distance.
b. An increase in mass caused an increase in kinetic energy.
c. Some of the energy was transferred to the cup.
The image shows an apple falling from a window ledge 6 meters off the ground.
a. At which position is the potential energy the greatest?
(1 point)
Responses
6 m
6 m
4 m
4 m
2 m
2 m
0 m
0 m
Question 2
b. At what position is the kinetic energy the greatest?(1 point)
Responses
6 m
6 m
just below 6 m
just below 6 m
just above 0 m
just above 0 m
0 m
0 m
Question 3
c. What is happening to potential energy as the ball is falling?(1 point)
Responses
Potential energy is decreasing.
Potential energy is decreasing.
Potential energy is increasing.
Potential energy is increasing.
Potential energy is staying the same.
Potential energy is staying the same.
It is impossible to tell.
It is impossible to tell.
Question 4
d. What is happening to kinetic energy as the ball is falling?(1 point)
Responses
Kinetic energy is decreasing.
Kinetic energy is decreasing.
Kinetic energy is increasing.
Kinetic energy is increasing.
Kinetic energy is staying the same.
Kinetic energy is staying the same.
It is impossible to tell.
It is impossible to tell.
Question 5
e. What is happening to total energy as the ball is falling?(1 point)
Responses
Total energy is decreasing.
Total energy is decreasing.
Total energy is increasing.
Total energy is increasing.
Total energy is staying the same.
Total energy is staying the same.
It is impossible to tell.
a. The potential energy is the greatest at a height of 6 m.
b. The kinetic energy is the greatest just above 0 m.
c. The potential energy is decreasing as the ball is falling.
d. The kinetic energy is increasing as the ball is falling.
e. The total energy is staying the same as the ball is falling.
Sharon and Bruce are playing basketball at a local park. When they take a break, they put the basketball on the brick wall that is near the bleachers. They notice that the basketball rolls off the wall and falls to the ground.
This makes them think about a school lesson about energy. Fill in the blanks from their conversation.
(4 points)
a. Sharon reminded Bruce that the basketball had energy as it fell. This energy of motion is called
. Bruce agreed and said this energy of motion was
right before the ball hit the ground.
b. Then Bruce recalled that the ball originally had stored energy as it sat on the wall. This stored energy is called
. Sharon explained that this stored energy
as the ball fell.
Question 2
Sharon and Bruce want to determine what type of energy the basketball has at various times.
c. Identify the type or types of energy described in each situation listed below.
You might click only one answer in each row, or you might click both answers in a row.
(3 points)
potential energy kinetic energy
The basketball is sitting on the wall.
potential energy – The basketball is sitting on the wall.
kinetic energy – The basketball is sitting on the wall.
The basketball is falling and is about half-way between the top and the bottom.
potential energy – The basketball is falling and is about half-way between the top and the bottom.
kinetic energy – The basketball is falling and is about half-way between the top and the bottom.
After the basketball hits the ground, it starts rolling across the ground in front of the wall.
a. Sharon reminded Bruce that the basketball had energy as it fell. This energy of motion is called kinetic energy. Bruce agreed and said this energy of motion was highest right before the ball hit the ground.
b. Then Bruce recalled that the ball originally had stored energy as it sat on the wall. This stored energy is called potential energy. Sharon explained that this stored energy converted to kinetic energy as the ball fell.
c. The basketball is sitting on the wall - potential energy
The basketball is falling and is about halfway between the top and the bottom - both potential energy and kinetic energy
After the basketball hits the ground, it starts rolling across the ground in front of the wall - kinetic energy
Ms. Smith is teaching a lesson about energy. She has her students evaluate her activities as she teaches the lesson.
Which of Ms. Smith's activities show energy transfer?
(4 points)
This DOES show an energy transfer to an object. This does NOT show an energy transfer to an object.
Ms. Smith pushes her markers out of the way so she can put her papers on the table.
This DOES show an energy transfer to an object. – Ms. Smith pushes her markers out of the way so she can put her papers on the table.
This does NOT show an energy transfer to an object. – Ms. Smith pushes her markers out of the way so she can put her papers on the table.
Ms. Smith throws a piece of trash into the trash can.
This DOES show an energy transfer to an object. – Ms. Smith throws a piece of trash into the trash can.
This does NOT show an energy transfer to an object. – Ms. Smith throws a piece of trash into the trash can.
Ms. Smith waits patiently while her students settle into their seats.
This DOES show an energy transfer to an object. – Ms. Smith waits patiently while her students settle into their seats.
This does NOT show an energy transfer to an object. – Ms. Smith waits patiently while her students settle into their seats.
Ms. Smith picks up a book, drops it, and allows it to hit the floor.