Power, Work, & Force vs. Distance

Which graph shows the greatest amount of work:

• 1

• 2

• 3

• 4

The chart represents the work output and the time to do the work for four machines. For which machine is the power output least?

• I

• II

• III

• IV

A girl carries a heavy suitcase quickly up a flight of stairs. A boy of the same weight carries the same suitcase slowly up the flight of stairs. Which statement is true?

• The girl did less work and had less power than the boy.

• The girl had less power than the boy.

• The girl did more work and had more power than the boy.

• The girl had more power than the boy.

A child pulls a toy car along a smooth, frictionless floor. The forces in newtons (N) and distances in meters (m) are shown in the graph below. Based on the information in the graph, which of the following represents the correct amount of work in joules (J) to pull the car 8 m?

• 3 J

• 16 J

• 32 J

• 90 J

A student was producing 75 watts of power while applying a constant force of 225N to slide a box of books 2.0 m across the floor. How long did it take the student to slide the box of books?

• 0.17 s

• 0.67 s

• 3.0 s

• 6.0 s