S10 Phys - Power and efficiency

Work is measured in:

• Watts

• Joules

• Newtons

• Kg

Power is measured in:

• Watts

• Joules

• Newtons

• Kg

1 horsepower is about equal to

• 750 W

• 100 W

• 250 W

• 1000 W

Power denotes

• The amount of energy used in a period of time

• The total amount of energy used to do an action

• The time that it takes to do a task

• The amount of potential energy gained

Which of the scenarios would require the most power?

• Car driving up a steep hill slowly

• Car driving up a steep hill quickly

• Car driving on a level surface quickly

• Car driving down a steep hill slowly

If power is needed to maintain a velocity, the energy has been used to counteract

• Friction

• Kinetic energy change

• Chemical energy change

• The destruction of energy

Work requires all of the following except:

• Time

• Force

• Displacement

Change in time is calculated as

• Final - initial

• Initial - final

• Final + initial

• Final/initial

True or false: Power can be calculated from work or energy.

• True

• False

The SI unit for power is the

• Watt

• Horsepower

• Joule

• Newton