Energy Review, Part 1

What is the scientific meaning of energy?

• anything that has mass

• the ability to cause change

• anything that cannot be seen

• the property of something to take up space

Which of these is an example of the conversion of gravitational potential energy into kinetic energy?

• a person running on a level track

• an apple falling from a tree to the ground

• a wind-up spring making a toy car move acroos the floor

• a rubber band being stretched to twice its normal length

Mechanical energy is the sum of two types of energy-kinetic energy and potential energy of position. Which of the following is an example of an object that has kinetic energy?

• a snail crawling across a leaf

• a computer monitor sitting on a desk

• a tightly wound spring in a windup toy

• a roller coaster car just before it goes downhill

Matt and Kim use bowling balls with different masses. If they both roll their bowling balls at exactly the same speed, which claim could be supported by the evidence?

• The bowling ball with less mass has more kinetic energy.

• The bowling ball with more mass has more kinetic energy.

• The kinetic energies of the two bowling balls are the same.

• There is not enough information to compare the kinetic energies.

Which of these is an example of the conversion of kinetic energy into gravitational potential energy?

• a bicyclist coasting down a long hill

• a car engine moving the car forward

• a roller coaster car moving toward the top of a rise in the tracks

• a thrown ball falling toward the ground after passing through the top part of its motion

Which of these is an example of the conversion of elastic potential energy into kinetic energy?

• a person running on a level track

• an apple falling from a tree to the ground

• a windup spring making a toy car move across the floor

• a rubber band that is being stretched to twice its normal length

Which of these is an example of kinetic energy?

• wind blowing

• water in a glass

• a can of vegetables

• the walls of a building

Ignacio uses a hammer to hit a nail into a board on the floor. How does gravity make it easier to hammer the nail?

• Gravity pushes the board up to help the nail go in.

• Gravity pulls the board and the nail toward each other.

• Gravity pulls the hammer down so that it pushes on the nail.

• Gravity pulls the nail down but does not pull on the hammer.

The law of conservation of energy describes how the amount of total energy can change in a closed system. Which of these statements correctly describes this law?

• The amount of kinetic energy in a system is a constant value.

• Energy can be converted from one form into another, but it cannot be created or destroyed.

• An object can have potential energy or kinetic energy, but not both at the same time.

• The amount of energy created when an object moves is equal to the energy destroyed when it stops moving.

Tyler has learned that potential energy is energy stored. Tyler's teacher asks the students to come up with a demonstration of potential energy. Which of the following would best work for this demonstration?

• A parked car in the driveway.

• Wheels spinning on the ground.

• A rock after it has been thrown.

• A child at the top of a slide.