Power Review

The rate at which work is done.

• Power

• Kilowatt-Hour

• Joule

• Watt

The SI unit of power.

• Power

• Kilowatt-Hour

• Joule

• Watt

The SI unit of work.

• Efficiency

• Kilowatt-Hour

• Joule

• Watt

For a given resistor at a particular temperature, the current is directly proportional to the applied voltage.

• Power

• Ohm's Law

• Joule

• Efficiency

Because of energy dissipation (friction, heat), the output power of any machine is always ________ than the input power.

• less

• more

• the same

• double

When you run up a flight of stairs, you do the _________ amount of work as when you walk up the stairs, but when you run up the stairs you use __________ power than when you walk up the stairs.

• same, more

• more, same

• same, less

• less, more

Electric utility companies are sometimes called “power companies,” but they really sell ___________, not power.

• gasoline

• engines

• horsepower

• energy

Electric utility companies could charge for the number of Joules, or Watt-seconds, but that is a small amount of energy. Instead they charge by the -

• Newton minute

• Kilowatt hour

• Coulomb second

• Voltage

The weight lifter used a force of 980 N to raise the barbell over her head in 5.21 seconds. Approximately how much power did she use in raising the barbell?

• 384 W

• 645 W

• 884 W

• 995 W

The percentage of the output pwer to the input power in an engine.

• Efficiency

• Ohm's Law

• Joule

• Watt