Unit Review

Question 1 of 17

An engineer has created a new engine for race cars. To find out which fuel mixture performed best in the engine, which experimental design would you choose?

A. Use one fuel mixture in the engine and measure its performance

B. Use one fuel mixture in the new engine and several other different engines and measure their performance

C. Use different fuel mixtures on the new engine and measure its performance

D. Use different fuel mixtures on the new engine and several other different engines and measure their performance

Question 2 of 17

To measure the percentage efficiency of an electrical power plant and transmission system, you should ___________________.

A. Divide the total energy input by the total energy output

B. Divide the energy output by the total energy input

C. Divide the total energy lost by the total energy output

D. Divide the total energy output by the total energy lost

Question 3 of 17

Not all of the energy that is put into a combustion heat engine results in useful output. What happens to most of this "lost" energy?

A. It dissipates as heat

B. It is exhausted from the engine due to incomplete combustion

C. It dissipates due to friction

D. It is stored inside the engine and used for other processes

Question 4 of 17

According to the diagram, what percentage of the energy in the fuel is actually used to propel the vehicle?

A. 7-10 percent

B. 100 percent

C. 72-85 percent

D. 15-28 percent

Question 5 of 17

Assuming the same energy input, as a machine's efficiency increases, its work output ___________________.

A. Decreases

B. Stays the same

C. Increases

D. Not enough information to determine

Question 6 of 17

According to the table, what is the most efficient part of the process of converting a fossil fuel to electricity?

A. Chemical to thermal energy

B. Turbine spinning the electric generator

C. Conversion of water to steam

D. Transmission through power lines

Question 7 of 17

What unit of measurement could you use to measure the energy it takes to skateboard?

A. Calories

B. Joules

C. British thermal units (Btu)

D. Any of the above

Question 8 of 17

What is the efficiency of the toaster in the diagram?

A. 25 percent

B. 50 percent

C. 30 percent

D. 125 percent

Question 9 of 17

The efficiency of any machine is less than 100 percent because of losses due to friction. Energy lost due to friction is converted into ___________________.

A. Thermal energy

B. Chemical energy

C. Electrical energy

D. Potential energy

Question 10 of 17

How much energy is needed to run a 60-watt light bulb for three seconds?

A. 20 joules

B. 30 joules

C. 60 joules

D. 180 joules

Question 11 of 17

According to _______, energy can change from one form to another or be transferred from one object to another, but the total amount of energy in a system remains constant.

A. The first law of thermodynamics

B. The second law of thermodynamics

C. The law of conservation of energy

D. The law of conservation of mass

Question 12 of 17

How many calories of energy does it take to increase the temperature of 400 grams of water by 10 degrees Celsius?

A. 40 calories

B. 4,000 calories

C. 400 calories

D. Not enough information to determine

Question 13 of 17

The energy content of the fuels in this table is expressed in what units?

A. Joules

B. Watts

C. Calories

D. Btu

Question 14 of 17

An example of a system that converts, transmits, and controls energy to perform useful work is ___________________.

A. An electric power plant

B. A power system

C. An automobile

D. All of the above

Question 15 of 17

Electric power is typically measured in what units?