Work and Power Worksheet
Section 5-1 and 5-4
Name
Period
1. Apply the work equation to determine the amount of work
done by the applied force in each of the three situations
described below.
2. Ben Travlun carries a 200-N suitcase up three flights of stairs (a height of 10.0 m) and then pushes it with a
horizontal force of 50.0 N at a constant speed of 0.5 m/s for a horizontal distance of 35.0 meters. How much
work does Ben do on his suitcase during this entire motion?
3. Before beginning its initial descent, a roller coaster car is always pulled up the first hill to a high initial height.
Work is done on the car (usually by a chain) to achieve this initial height. A coaster designer is considering three
different incline angles at which to drag the 2000-kg car train to the top of the 60-meter high hill. In each case,
the force applied to the car will be applied parallel to the hill. Her critical question is: which angle would require
the most work? Analyze the data, determine the work done in each case, and answer this critical question.
Angle
35 deg
45 deg
55 deg
Force
1.12 x 104 N
1.39 x 104 N
1.61 x 104 N
Distance
105 m
84.9 m
73.2 m
4. A force of 50 N acts on the block at the angle shown in the
diagram. The block moves a horizontal distance of 3.0 m. How
much work is done by the applied force?
Work (J)
5. How much work is done by an applied force to lift a 15-Newton block 3.0 meters vertically at a constant speed?
6. A student with a mass of 80.0 kg runs up three flights of stairs in 12.0 sec. The student has gone a vertical
distance of 8.0 m. Determine the amount of work done by the student to elevate his body to this height. Assume
that her speed is constant.
7. Calculate the work done by a 2.0-N force (directed at a 30° angle
to the vertical) to move a 500 gram box a horizontal distance of
400 cm across a rough floor at a constant speed of 0.5 m/s.
(HINT: Be cautious with the units.)
8. A tired squirrel (mass of 1 kg) does push-ups by applying a force
to elevate its center-of-mass by 5 cm. Estimate the number of
push-ups which a tired squirrel must do in order to do a
approximately 5.0 Joules of work.
POWER PROBLEMS
9. Suppose that Ben Pumpiniron elevates his 80-kg body up the 2.0 meter stairwell in 1.8
seconds. If this were the case, then we could calculate Ben's power rating.
10. Two physics students, Will N. Andable and Ben Pumpiniron, are in the weightlifting room. Will lifts the 100pound barbell over his head 10 times in one minute; Ben lifts the 100-pound barbell over his head 10 times in 10
seconds. Which student does the most work? Which student delivers the most power? Explain your answers.
11. During a physics lab, Jack and Jill ran up a hill. Jack is twice as massive as Jill; yet Jill ascends the same distance in
half the time. Who did the most work? Who delivered the most power? Explain your answers.
12. A tired squirrel (mass of approximately 1 kg) does push-ups by applying a force to elevate its center-of-mass by
5 cm in order to do a mere 0.50 Joule of work. If the tired squirrel does all this work in 2 seconds, then
determine its power.
13. When doing a chin-up, a physics student lifts her 42.0-kg body a distance of 0.25 meters in 2 seconds. What is
the power delivered by the student's biceps?
14. Your household's monthly electric bill is often expressed in kilowatt-hours. One kilowatt-hour is the amount of
energy delivered by the flow of l kilowatt of electricity for one hour. Use conversion factors to show how many
joules of energy you get when you buy 1 kilowatt-hour of electricity.
15. An escalator is used to move 20 passengers every minute from the first floor of a department store to the
second. The second floor is located 5.20 meters above the first floor. The average passenger's mass is 54.9 kg.
Determine the power requirement of the escalator in order to move this number of passengers in this amount
of time.