Energy Transformations
A student turns on a flashlight. Which energy transformation occurs in the flashlight system?
A. Electrical energy to chemical energy
B. Chemical energy to electrical energy to light energy
C. Thermal energy to sound energy
D. Light energy to motion energy
B. Chemical energy to electrical energy to light energy
A student makes the claim that energy can change from one form to another in a system.
Which example best supports the claim?
A. A battery-powered fan spins and produces sound
B. A glass of water remains on a table
C. A book stays on a shelf
D. A pencil lies on a desk
A. A battery-powered fan spins and produces sound
A distance-time graph shows a flat line from 2 seconds to 5 seconds.
What does this indicate about the object’s motion during that time?
A. The object is speeding up
B. The object is slowing down
C. The object is not changing position
D. The object is moving at a constant fast speed
C. The object is not changing position
A student rides a bicycle down a hill.
As the bicycle speeds up, what happens to the student’s kinetic energy?
A. It decreases
B. It stays the same
C. It increases
D. It becomes potential energy only
C. It increases
Which statement best explains why a device that gives off light and heat shows more than one energy transformation?
A. The device contains more than one type of matter
B. The device transforms energy into more than one output form
C. The device creates energy as it operates
D. The device stores only electrical energy
B. The device transforms energy into more than one output form
A hair dryer is plugged into an outlet and begins blowing warm air.
Which statement best describes the energy transformations in the system?
A. Electrical energy is transformed into thermal energy and motion energy
B. Thermal energy is transformed into electrical energy and sound energy
C. Motion energy is transformed into chemical energy
D. Light energy is transformed into thermal energy
A. Electrical energy is transformed into thermal energy and motion energy
A student claims that a moving object has kinetic energy.
Which observation best supports the claim?
A. The object has mass and is in motion
B. The object is blue and smooth
C. The object is resting on a surface
D. The object was made in a factory
A. The object has mass and is in motion
A velocity-time graph shows an upward sloping line.
What does this indicate about the object’s motion?
A. The object is stopped
B. The object’s velocity is increasing
C. The object’s distance is constant
D. The object’s mass is increasing
B. The object’s velocity is increasing
A ball is held at the top of a ramp and then released.
Which statement best describes the energy changes as the ball rolls down the ramp?
A. Kinetic energy changes into potential energy
B. Potential energy changes into kinetic energy
C. Thermal energy changes into light energy
D. Electrical energy changes into sound energy
B. Potential energy changes into kinetic energy
A student says that if an object is not moving, it has no kinetic energy.
Which statement best evaluates the claim?
A. The claim is correct because kinetic energy depends on motion
B. The claim is incorrect because all objects have kinetic energy
C. The claim is incorrect because mass does not matter
D. The claim is correct because potential energy and kinetic energy are always equal
A. The claim is correct because kinetic energy depends on motion
A student observes an incandescent light bulb after it is turned on. The bulb produces light and becomes warm.
Which statement best explains the energy transformations in this system?
A. Electrical energy is transformed into light energy only
B. Electrical energy is transformed into thermal energy only
C. Electrical energy is transformed into light energy and thermal energy
D. Thermal energy is transformed into electrical energy and light energy
C. Electrical energy is transformed into light energy and thermal energy
A student observes an incandescent light bulb after it is turned on. The bulb produces light and becomes warm. The student makes the claim that the bulb demonstrates more than one energy transformation.
Which evidence best supports the student’s claim?
A. The bulb is made of glass and connected to a wire
B. The bulb changes electrical energy into light energy and thermal energy
C. The bulb is brighter than some other types of bulbs
B. The bulb changes electrical energy into light energy and thermal energy
A velocity-time graph shows a horizontal line above zero.
What can be concluded about the object’s motion?
A. The object is not moving
B. The object is moving with constant velocity
C. The object is slowing down
D. The object is changing direction
B. The object is moving with constant velocity
Two objects move at the same speed, but one object has more mass.
Which object has more kinetic energy?
A. The object with more mass
B. The object with less mass
C. Both have the same kinetic energy
D. There is not enough information because speed does not matter
A. The object with more mass
A vehicle’s velocity remains the same for 4 seconds.
Which statement best describes the vehicle’s kinetic energy during that interval?
A. It increases
B. It decreases
C. It stays constant
D. It changes direction
C. It stays constant
A toaster is operating. The heating coils glow red, and the bread becomes warmer.
Which statement best describes the energy transformations in the toaster?
A. Electrical energy is transformed into thermal energy and light energy
B. Motion energy is transformed into electrical energy
C. Chemical energy is transformed into nuclear energy
D. Thermal energy is transformed into electrical energy
A. Electrical energy is transformed into thermal energy and light energy
A student observes a battery-powered toy car moving across the floor and making sound.
Which claim is best supported by the evidence?
A. The toy car destroys energy as it moves
B. Chemical energy is transformed into motion energy and sound energy
C. Sound energy is transformed into chemical energy
D. The battery stores only thermal energy
B. Chemical energy is transformed into motion energy and sound energy
A vehicle’s velocity increases from 0 m/s to 20 m/s.
What happens to the vehicle’s kinetic energy?
A. It decreases
B. It stays the same
C. It increases
D. It disappears
C. It increases
A student pushes a box across the floor.
After the student stops pushing, the box slows down. Which statement best explains why the box loses kinetic energy?
A. The box loses mass as it moves
B. Friction transforms some kinetic energy into thermal energy
C. Gravity changes kinetic energy into electrical energy
D. The floor transforms sound energy into motion energy
B. Friction transforms some kinetic energy into thermal energy
A student looks at a velocity-time graph and selects a kinetic energy graph with the exact same straight-line shape.
What error is the student most likely making?
A. The student is assuming kinetic energy is unrelated to motion
B. The student is confusing mass with velocity
C. The student is assuming kinetic energy changes in exactly the same way as velocity
D. The student is assuming the object is not moving
C. The student is assuming kinetic energy changes in exactly the same way as velocity
A student claims that a lamp only transforms electrical energy into light energy.
Which observation best evaluates the claim?
A. The lamp is made of metal and glass
B. The lamp also becomes warm while it is on
C. The lamp is plugged into a wall outlet
D. The lamp produces the same amount of light each day
B. The lamp also becomes warm while it is on
A student states that when a device becomes warmer while operating, some energy has been transformed into thermal energy.
Which example best supports this claim?
A. A flashlight becomes warm after being on for several minutes
B. A battery is stored in a drawer
C. A lamp is turned off during the day
D. A wire is disconnected from a power source
A. A flashlight becomes warm after being on for several minutes
A graph shows the velocity of a vehicle increasing, then staying constant, then increasing again.
Which pattern best describes the kinetic energy of the vehicle?
A. Decrease, constant, decrease
B. Increase, constant, increase
C. Constant, decrease, constant
D. Increase, decrease, increase
B. Increase, constant, increase
A car moves at a constant velocity for several seconds and then speeds up.
Which statement best compares the car’s kinetic energy during both parts of the motion?
A. Kinetic energy decreases, then stays constant
B. Kinetic energy stays constant, then increases
C. Kinetic energy increases, then decreases
D. Kinetic energy stays constant during both parts
B. Kinetic energy stays constant, then increases
A student claims that a flat section on a distance-time graph means the object is moving at a constant speed.
Which statement best evaluates the claim?
A. The claim is correct because flat lines always show constant motion
B. The claim is correct because distance increases at the same rate
C. The claim is incorrect because a flat line means the distance is not changing
D. The claim is incorrect because speed and distance are unrelated
C. The claim is incorrect because a flat line means the distance is not changing