Speed & Kinetic Energy
Two identical wagons are moving. Wagon A moves 3 m/s and Wagon B moves 7 m/s. Which has more kinetic energy?
Wagon B
What usually changes when two moving objects collide: their mass, state of matter, or motion?
Motion
When two moving objects collide, what can be transferred from one object to another?
Energy
Energy cannot be created or ______
Destroyed
A moving bowling ball hits a bowling ball at rest. What will most likely happen to the ball at rest?
It will begin to move.
If an object's kinetic energy increases, what happens to its speed?
It increases or moves faster.
Which is NOT a collision: a bat hitting a baseball, a catcher catching a baseball, or a baseball flying through the air?
A baseball flying through the air
A moving ball hits a ball at rest and causes it to move. What happened to some of the moving ball's energy?
It transferred to the ball at rest.
Friction during a collision can change some kinetic energy into what form of energy?
Heat
A pool ball strikes another pool ball. Besides causing the second ball to move, what else might you observe?
A sound
Four identical wagons travel at 2, 4, 6, and 8 m/s. Which has the most kinetic energy?
The wagon moving 8 m/s
Why can the motion of two objects change when they collide?
Energy is transferred between the objects.
A hammer strikes a nail. Which object transfers kinetic energy to the other?
The hammer transfers energy to the nail.
Complete the statement: Energy can be ______ or ______, but it cannot be made or destroyed.
Transformed or transferred
A marble is released from different heights on a ramp and hits a stopper. Which release position would cause the stopper to move the farthest?
The highest position
Two identical balls roll down the same ramp. Ball A starts near the bottom and Ball B starts at the top. Which will most likely be moving faster at the bottom of the ramp?
Ball B
Two metal spheres roll toward each other and collide. Name one thing about their motion that could change.
Speed and/or direction
A moving black bowling ball strikes a gray bowling ball sitting still. Will the black ball transfer all, some, or none of its energy to the gray ball?
Some of its energy
A collision produces motion, sound, and heat. Does this mean energy was destroyed?
No. The energy was transferred or transformed into other forms.
Car B rolls down a ramp and collides with Car A sitting at the bottom. Give two observations you could make after the collision.
Car A may move; Car B may slow down/change direction; sound or heat may be produced.
Two identical marbles hit identical blocks. Marble A is moving slowly and Marble B is moving very fast. Predict which block will move farther and explain why
The block hit by Marble B because the faster marble has more kinetic energy to transfer.
A student says, “Objects only change motion during a collision if one object stops completely.” Is the student correct?
No. A collision can change an object's speed or direction without making it stop completely.
A moving puck collides with a stationary puck. Afterward, the stationary puck travels a long distance. What does this tell you about the collision?
Kinetic energy was transferred to the stationary puck, causing its motion to change.
A student says, “When a ball slows down after a collision, its missing energy has been destroyed.” Correct the student.
The energy was not destroyed; it was transferred to another object or transformed into forms such as heat or sound.
A marble is released from the highest point on a ramp and strikes a stationary object. Predict how this result would compare with releasing the marble from the lowest point. Explain using speed and energy.
From the highest point, the marble will be moving faster, have more kinetic energy, and transfer more energy during the collision, causing a greater change in motion.