Unit 6/7 Review

Which of the following does the Law of Conservation of energy state? (2 answers)

• An object will not change its motion unless acted upon by a force of energy.

• Energy cannot be created or destroyed

• An object at rest will stay at rest.

• The acceleration of an object depends upon the mass and the amount of force applied.

• Energy can change from one form to another.

"Absolute zero" is defined as the ___

• Theoretical temperature at which molecular motion stops

• Limit at which no further thermal energy can be added

• Temperature at which stars are created

• Amount of kinetic energy required to trigger a change in inertia

A student records the temperature of water during an experiment and gets the following results shown in the picture.

These results indicate that the molecules of water are _____

• increasing in movement

• slowing in movement

• absorbing thermal energy from the air

• condensing into water vapor

The melting/freezing point of mercury is -39⁰C. A scientist put liquid mercury into a freezer that is kept at a constant temperature of -35⁰C. Will the liquid mercury freeze?

• Yes, because the freezer is cold enough to freeze mercury.

• Yes, because the particles will slow down enough for the mercury to freeze.

• No, because the freezer isn't cold enough to freeze mercury.

• No, because there is not enough energy in the freezer to freeze the mercury.

A student conducts an experiment in which three brands of solar cells are attached to a toy car one at a time as shown.

When the student shines a flashlight on each solar cell, the car moves forward. Which best explains why this happens?

• The thermal energy of the car is being transformed into radiant energy.

• The solar cell absorbs thermal energy from the atmosphere.

• The flashlight harnesses radiant energy from the sun.

• The solar cell turns the radiant energy into electrical energy.

A Student conducts an experiment in which three brands of solar cells are attached to a toy car one at a time.The student then shines a flashlight on each solar cell to measure the distance traveled.

Match each part of the experiment with the correct term.

toy car ​ ​ ​ (a)  

speed of car ​ (b)  

solar cells ​ (c)  

• constant
• dependent variable
• independent variable

The numbers below show the temperature at which various events occur in Celsius and in Kelvin. Drag and drop the correct numbers into the correct place.

Kelvin - Absolute zero ​ (a)  

Kelvin - water boils ​ (b)  

Celsius - Absolute zero ​ (c)  

Celsius - water boils ​ (d)  

• 0
• 373
• -273
• 100

Which of the following instruments measures the kinetic energy of molecules in a substance?

• a

• b

• c

• d

The sun produces what kind of energy?

• electrical

• mechanical

• radiant

• chemical

Which of the following statements best describes what is happening in these models?

( 2 answers)

• The substance has turned into plasma.

• The substance has changed from a gas to a liquid

• The kinetic energy of the molecules has increased.

• The temperature of the substance has increased.

• Thermal energy in the substance has decreased.