Lesson 1: Work & Power

Multiple Choice

Which of the following is true about work?

• It measures how quickly an object accelerates
• It measures how much effort is applied over a distance.
• It measures the change of an object's rate of speed.
• It measures how much time it takes to move an object.

Multiple Choice

In which of these cases is work being done? 

• A student sleeps all night.
• A student pushes a locked door that does not move.
• A student carries his chair into another room.
• A student sits on the carpet.

Multiple Choice

Two people are lifting the same weight as shown in the animation. If they both do 10 reps, who will supply the most power?

• Bro A

• Bro B

• They both will do the same work

• Can't tell without knowing the weight they are lifting

Multiple Choice

The formula for power is

• work/time (P = W/t)

• force × distance (W = Fd)

• distance/time (s = d/t)

• mass × acceleration (F = ma)

Multiple Choice

Joel and Jerry push against a car that has stalled, trying unsuccessfully to get it moving. Jerry stops after 10 min, while Joel is able to push for 5.0 min longer. Compare the work they do on the car.

• Joel does 75% more work than Jerry.

• Joel does 50% more work than Jerry.

• Jerry does 50% more work than Joel.

• Joel does 25% more work than Jerry.

• Neither of them does any work.