Work and Power
Check Your Understanding
Instructions: Use your understanding of work and power to answer the following questions.
1. Two physics students, Harry Biceps and Ben Pumpiniron, are in the
weightlifting room. Harry lifts the 100-pound barbell over his head 10 times in one
minute; Ben lifts the 100-pound barbell over his head 10 times in 10 seconds.
A)Which student does the most work?
B) Which student delivers the most power? Explain your answers.
2. In search of a container of dihydrogen monoxide (H2O), Jack and Jill ran up the
hill. Jack is twice as massive as Jill; yet Jill climbed the same distance in half the
time.
A)Who did the most work?
B) Who delivered the most power? Explain your answers.
3. A beefy squirrel (weighing 1 Newton) does push-ups by applying a force to lift
his scrawny body by 5 cm.
a) Determine the number of push-ups which this squirrel must do in
order to do a mere 1.0 Joule of work. (HINT: Convert 5 cm =0.05 m)
b) If the squirrel does all this work in 4 seconds, then determine his
power.
4. If little Suzie Swingset lifts her 100-Newton body a distance of 0.25 meters in
2.0 seconds, then what is the power delivered by little Suzie’s legs?
5. Johnny Couchpotato fell asleep on the living room sofa with the lights still on.
He slept there for 5 hours. If each of his two lamps has a 60-Watt bulb in it, how
much work was needed to keep the lights on while he slept? (HINT: Change
hours to seconds!)
6. 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-meters above the
first floor. The average passenger's weight is 600 Newtons. Determine the power
requirement of the escalator in order to move this number of passengers in
this amount of time.