Unit 3 Energy Test Review

Unit 3a Energy Test

Review and Practice

Energy is the ability to do work or cause change.

Multiple Select

Check all the answers that apply. Energy is the ability to

• Do work

• Cause change

• Change shapes

• Change direction

Potential Energy

Energy that is stored based on an objects location or state.

Multiple Choice

Which of the following is an example of potential energy?

• a phone sitting on a desk

• a car driving down the road

• a rubber band flying through the air

• a pot with boiling water

Gravitational Potential Energy

Gravitational Potential Energy

• Influenced by mass

• More mass = more GPE

Gravitational Potential Energy

• The further something is from the ground the more potential energy it has

• Higher up = more GPE

Multiple Select

Select all the factors that influence gravitational potential energy.

• Hardness

• Mass

• Amount of stretch

• Amount of compression

• Distance from the ground

Multiple Choice

Books are sitting on a bookshelf. Which book has the greatest gravitational potential energy?

• a 1 lb book 1 foot away from the ground

• a 1 lb book 3 feet away from the ground

• a 2 lb book 1 foot away from the ground

• a 2 lb book 3 feet away from the ground

Multiple Choice

The diagram shows two frogs sitting on a bookshelf. Both frogs weigh 5 ounces. Frog A (left) is 4 feet off of the floor. Frog B (right) is sitting 2 feet off of the floor.

How can you describe the potential energy of the two Frogs?

• Neither frog has potential energy

• Both frogs have the same potential energy

• Frog A has more potential energy than frog B

• Frog B has more potential energy than frog A

Multiple Choice

The diagram shows two frogs sitting on a bookshelf. Both frogs weigh 5 ounces. Frog A (left) is 4 feet off of the floor. Frog B (right) is sitting 2 feet off of the floor.

How can you decrease the potential energy of frog A?

• Put frog A on a higher shelf.

• Put frog A on a lower shelf.

• Increase the weight of frog A.

• Put frog A on top of the bookshelf.

Potential Elastic Energy

• Another form of potential energy

• Has to do with being stretched or compressed

THREE things impact elastic energy!

#1 Impact - Stretching

Stretching something stores energy. Stretching it more stores more energy.

#2 Impact - Compression

Squishing something stores elastic energy. If you compress it more, you store more energy.

#3 Impact - How hard it is to stretch or compress something also impacts elastic energy.

Energy in = energy stored

When you put more energy into stretching or compressing something, that extra energy is stored in the object as elastic potential energy.

Harder materials need more force applied to change the shape.

Energy can transform from one type to another. Potential > Kinetic > Elastic

Multiple Select

Select all the factors that influence elastic potential energy. Hint: There are THREE!!!

• Hardness

• Mass

• Amount of stretch

• Amount of compression

• Distance from the ground

Multiple Select

Someone is bouncing a ball. What types of energy are involved in bouncing the ball? Select all that apply. Hint: There are THREE

• potential gravitational energy

• potential elastic energy

• kinetic energy

• bounce energy

Energy Relationships

• On tests you may see a chart like this showing 2 objects.

• The column shows us how much of each energy type the object has.

• Example: Car A has the most gravitational potential energy and the least kinetic energy.

• Read the column to learn about the object

Multiple Choice

This diagram shows a ball bouncing. In position A, the ball has hit the ground and is compressed. In position B, the ball is halfway in the air. In position C, the ball is at the highest point in the bounce.

Which table shows the correct relationship between gravitational potential energy and elastic energy?

• Amount of compression

Gravitational Energy and Kinetic Energy

• Gravitational energy and potential energy are always exchanging

• At the highest point an object has the most potential energy and the least kinetic energy

• At the lowest point the object has the most kinetic energy and the least potential energy

• In the middle the object will be a mix of potential and kinetic

Energy Relationships

• On tests you may see a chart like this showing 2 objects.

• The column shows us how much of each energy type the object has.

• Example: Car A has the most gravitational potential energy and the least kinetic energy.

• Read the column to learn about the object

Multiple Choice

A roller coaster is on a track. This picture shows 4 possible positions for the roller coaster.

Which table shows the correct relationship between gravitational potential energy and kinetic energy?

Multiple Choice

Ms. Welch, the seventh-grade science teacher, set up a pendulum in the science classroom. The pendulum is an object suspended on a string and allowed to swing back and forth. She starts the pendulum swinging. The picture shows the position of the pendulum as it swings from left to right.

At which position is the potential energy of the pendulum the greatest?

• A

• B

• C

• D

Multiple Choice

Ms. Welch, the seventh-grade science teacher, set up a pendulum in the science classroom. The pendulum is an object suspended on a string and allowed to swing back and forth. She starts the pendulum swinging. The picture shows the position of the pendulum as it swings from left to right.

At which position is the kinetic energy of the pendulum the least?

• A

• B

• C

• D

Multiple Choice

Ms. Welch, the seventh-grade science teacher, set up a pendulum in the science classroom. The pendulum is an object suspended on a string and allowed to swing back and forth. She starts the pendulum swinging. The picture shows the position of the pendulum as it swings from left to right.

At which position is the kinetic energy of the pendulum the greatest?

• A

• B

• C

• D

Multiple Choice

Ms. Welch, the seventh-grade science teacher, set up a pendulum in the science classroom. The pendulum is an object suspended on a string and allowed to swing back and forth. She starts the pendulum swinging. The picture shows the position of the pendulum as it swings from left to right.

What form of energy does the pendulum represent?

• Radiant energy

• Elastic energy

• Chemical energy

• Mechanical energy

Thermal Energy

The faster something's particles are moving, the hotter it will feel. This is thermal energy.

Multiple Choice

Particles in a warmer block will have ________ kinetic energy and move ______than the particles in the colder block.

• more/slower

• less/slower

• less/faster

• more/faster

Thermal Energy Movement

Thermal energy always moves from the hotter object to the cooler object.

The particles bump and shove each other until the cooler ones are also moving quickly.

It stops when both things are the same temperature.

Multiple Choice

A mug is cool when it is in the cabinet. After hot water is added, it is too hot to hold comfortably.

Choose the best explanation for this scenario:

• As the temperature of the mug increased due to the hot water, the particles in the mug moved slower and the thermal energy increased.

• As the temperature of the mug increased due to the hot water, the particles in the mug moved slower and the thermal energy decreased.

• As the temperature of the mug increased due to the hot water, the particles in the mug moved faster and the thermal energy increased.

• As the temperature of the mug increased due to the hot water, the particles in the mug moved faster and the thermal energy decreased.

Multiple Choice

Which best describes the transfer of heat due to the movement of gases or liquids?

• radiation

• convection

• evaporation

• condensation

Multiple Choice

Select the arrow that would accurately diagram this thermal energy transfer

• ↺

• ↻

• ←

• →

Multiple Choice

Which example shows us an example of conduction?

• lava lamp

• fire

• spoon in soup

Multiple Choice

Which letter is an example of radiation?

• A

• B

• C

Multiple Choice

Which mug has the largest amount of thermal energy?

a. Is a small mug. It is 100°F

b. Is a large mug. It is 120°F

c. Is a small mug. It is 120°F

• A

• B

• C

Multiple Select

An ice cube with food coloring is placed in a glass of room temperature water. Dye begins to drop down from the ice cube to the bottom of the glass. Which of the following statements are true about the image?

• Cold dye is more dense than hot dye

• Particles in cold dye move more quickly

• Particles in cold dye move more slowly

• Particles in cold dye sink

• If the water were heated, the dye would spread out more quickly

Multiple Choice

Blobs in a lava lamp cool and drop down to the bottom of the lava lamp. Which of the following statements is true about this image?

• This is an example of convection

• This is an example of radiation

• This is an example of conduction

Open Energy Systems

Open systems allow energy and matter to come and go.

Closed Energy Systems

Closed energy systems only let energy come and go. Matter is trapped inside.

Isolated Energy Systems

Systems that NOTHING can come or go from are called isolated systems. There are no true isolated systems on Earth. The closest we can get is a thermos, cooler, or bank safe.

Multiple Choice

A hot pot with a closed lid is placed on a table. Something is placed in between the pot and the table to protect the table from heat. Why does the table need protection from heat?

• The pot is an open system, heat and matter can enter and leave the pot

• The pot is a closed system, heat can escape but matter cannot

• The pot is an isolated system, heat and energy cannot escape

• The pot is an open system, heat can escape but matter cannot

Energy is never created or destroyed.

Energy just transforms or transfers.

Multiple Choice

What does the Law of Conservation of Energy say about energy in the universe?

• Energy is constantly created

• Energy is constantly destroyed

• Energy is never created or destroyed

• All matter is being converted into energy

Multiple Choice

How do batteries supply energy to devices?

• They create energy to give to the device

• They store energy from another source for the device to use later

• They move chemical energy from the wall to the device

• They destroy leftover energy so it does not interfere with the device

Energy Transfers

Energy moves from one object to another object

Energy Transformation

Multiple Choice

Which device transforms mechanical energy into electrical energy?

• Wind turbine

• Fan

• Mixer

• Radio

Multiple Choice

Mrs. Kucalaba is using a battery operated drill to drill screws into a wood deck that she is building.

Which energy transformation explains how Mrs. Kucalaba was able to use a drill without an electrical cord being attached?

• Chemical energy was transformed into mechanical energy

• Mechanical energy was transformed into electrical energy

• Sound energy was transformed into electrical energy

• Kinetic energy was transformed into potential energy

Multiple Choice

Mrs. Kucalaba's drill is 75% energy efficient This means that 75% of the electricity used by the drill is used to drill holes or screw in screws.

Which statement best explains what happens to the other 25% of the electricity that goes into her drill?

• The leftover energy is destroyed

• The leftover energy is changed into heat and sound energy

• The left over energy is changed into chemical energy

• The leftover energy becomes potential electrical energy

Multiple Choice

Mrs. Cristell is bored. She decides to fidget with a paperclip. She grabs the paperclip and bends it repeatedly. It gets warm where she is bending it and then it breaks.

What type of energy transformation occurs when the metal is bent repeatedly?

• Heat energy to mechanical energy

• Metal energy to broken energy

• Mechanical energy to heat energy

• Boredom energy to fidget energy