When Frank pedals his bicycle, he is giving it _______ energy.
Mechanical
_____ allow energy to pass through them easily, while _____ resist and make it more difficult.
Conductors, Insulators
Electrical charges can be either positive or negative. Which of the following is true about electrically charged objects?
Jacob pushed a box of books across the garage floor, and the box moved forward.
When the box stopped moving, Jacob rested for a moment. Then, he put a force on the box a second time. This time, the box moved forward, but faster and farther than the first time.
What kind of force did Jacob put on the box the second time?
A. a push with more force
Anna is pushing her brother on a swing. Anna pushes her brother again in the same direction that he is already moving. What will happen to her brother?
B. He will swing faster and higher.
Which type of energy passes from a frying pan to an egg to cook it?
Thermal
Kayla boils a pot of water. What will happen when she sticks a metal spoon that is at room temperature into the boiling water?
The diagram below shows a light bulb connected to a battery by a wire.
What will happen to the light bulb?
Nothing, the circuit is incomplete
Jeremy throws his ball up in the air, but the ball falls back to the ground. What force made the ball move without ever touching the ball?
D. gravity pulling on the ball
A cannon fired a cannonball into the air. If there were no forces at all acting on the ball after it was fired, not even gravity, the ball would
D. not change speed or direction.
What are three types of energy produced by a television?
Light, Sound, Thermal
Sometimes manufacturers do not want heat to be conducted through certain parts, such as the handles of pots, the steering wheels in cars, and swings on playgrounds.
What material are these parts likely to be made out of?
A. plastic
Jessica's family decorated their house for the holidays. When they were finished, Jessica plugged in a string of lights they had put up.
When she plugged the lights in, what traveled through the electrical cord and created an electric current?
D. electrons
The harder a person hits a tennis ball, the faster it moves. Why does the ball move faster?
The _____ acting on the ball becomes ______.
Force, Greater
A force is a push or a pull. An object needs to be acted on by a force in order to do which of the following?
All of them!
Batteries can be produced by placing strips of metal into certain liquid solutions and then connecting the pieces of metal with wire.
What kind of energy is stored in the liquid solutions?
Chemical
When the blades of a fan move, they have mechanical energy.
This mechanical energy comes from
What will happen to the two objects in the picture as they are slowly moved toward each other?
They will push against (repel) each other
Which of the following forces can both attract and repel some objects without touching them?
D. magnetism
Monique and Jerry are playing with a toy car. Monique pushes the car, and the car moves toward Jerry. Without stopping the car, Jerry pushes it back toward Monique with a force that is greater than the force that Monique used.
Which of these best describes what happens to the toy car's motion when Jerry pushes the car?
How do objects produce sound waves?
They vibrate
The machines in a hydroelectric dam produce electrical energy for homes. Where do the machines get their energy from?
Flowing water
How is static electricity produced?
C. friction
Marc and Rick are pushing on opposite ends of the box shown above. Marc is pushing on the box with a force of 5 N. Rick is also pushing on the box with a force of 5 N. In which direction will the box move?
Friction is a force that acts between objects that are touching one another. Friction opposes motion, so it makes it harder for two objects to slide along each other.
For example, friction between a person's feet and the ground makes it possible for the person to walk because it keeps that person from slipping with each step.
Sometimes friction is helpful, as in the case of walking. But sometimes, such as when a sledder wants to go fast down a hill, it is not helpful.
In which of the cases below is friction most helpful?
What kind of vibration is required to create a low-pitched sound?
C. slow
Windmills are capable of capturing the _____ energy contained in moving wind and transforming it into _____ energy.
Mechanical, Electrical
A wool sweater is a positively charged object. Packing peanuts, like those shown in the picture, are small, negatively charged pieces of foam.
What happens when a packing peanut is held near a wool sweater?
The peanut will stick to the sweater.
A boy kicks a ball with a force of 40 N. At exactly the same moment, a gust of wind blows in the opposite direction of the kick with a force of 40 N.
What happened to the ball?
Mildred's teacher gave her a little motor and several toy cars. The motor fit inside the toy cars and could push each one with a steady force that was always the same. Mildred kept track of how fast the cars went. The graph below shows her measurements.
The masses of the three cars were different. Put the cars in order from least massive (lightest) to most massive (heaviest).
W, X, Y