UNIT D: ENERGY

Objects of different masses are suspended from a height. Which combination of features will have the greatest gravitational potential energy?

• Low mass and low height

• Low mass and high height

• High mass and high height

• High mass and low height

Which statement most accurately describes the Law of Conservation of Energy?

• Energy cannot be created or destroyed, but it can change from one type to another.

• Energy is created from the Earth and is destroyed when we use it.

• Energy should be saved (conserved) for use in the future.

• All forms of energy can be classified as either potential or kinetic.

The efficiency of an average gasoline powered car is about 20%. This means

• The gas tank needs to be 20% filled with gasoline for motion.

• The car uses 80% of the energy stored in the gasoline for motion.

• The car uses 20% of the energy stored in the gasoline for motion.

• The car wastes 20% of the energy stored in the gasoline.

What energy transformation takes place when a radio is plugged in and turned on?

• Kinetic to potential

• Electrical to sound

• Wire to radio waves

• Battery to motion

When you open the door to a refrigerator for a minute, what happens?

• Thermal energy in the refrigerator is transferred to the air outside the refrigerator.

• Thermal energy in the air outside the refrigerator is transferred to the inside of the refrigerator.

• The temperature of the air inside the refrigerator decreases.

• The temperature of the air just outside the refrigerator increases.

Which units are used for measuring energy?

• Pounds

• Meters

• Degrees Celsius

• Calories

Which list consists of only renewable energy sources?

• Solar, nuclear, coal, wind

• Wind, solar, hydro, tidal

• Nuclear, petroleum, wind, hydro

• Petroleum, tidal, solar, biomass

Cory noticed that the hood of the car was hot after driving it for a while. What energy transformation was she noticing?

• Chemical energy → thermal energy

• Thermal energy → motion (kinetic)

• Temperature energy → braking energy

• Motion (kinetic) → thermal energy

Which of the following methods will melt an ice cube the quickest?

• Hold it in your hand and change hands when one hand gets cold

• Put it in a glass of room temperature water

• Put it in an insulating container

• Break it into pieces and warm up the pieces

Jose had a 200mL cup of hot chocolate that was 95° which was too hot to drink. His mother suggested he add some cold milk to cool it off so he added 50 mL of milk which was 5° Celsius. What was the approximate temperature of Jose’s hot chocolate?

• 95° Celsius

• 75° Celsius

• 25° Celsius

• 5° Celsius