Work and Power Practice Problems

Work and Power Practice Problems worksheet #2
1. A 15kg mass is lifted upward at a constant speed to a height of 22 m. Calculate the work done by the
lifting force.
2. Calculate the power used in the problem above if it took 1 minute to lift the load.
3. How much work does a 100 Watt motor perform in 5 minutes?
4. A student who weighs 600N climbed the stairs from the second floor to the fourth floor, 20 meters
above, in 60 seconds.
a. How much work did she do?
b. What was her power?
5. A small motor does 4000J of work in 20 seconds. What is the power of the motor in watts?
6. A 100N load is lifted to a height of 5 m in 30 seconds. Calculate the power.
7. Lamar Gant, U.S. powerlifting star, became the first man to deadlift five times his own body weight in
1985. Deadlifting involves raising a loaded barbell from the floor to a position above the head with
outstretched arms. Determine the work done by Lamar in deadlifting 300 kg to a height of 0.90 m above
the ground.
8. If 2J of work is done in raising a 180g apple, how far was it lifted?
9. How long does it take a 19,000W steam engine to do 6.8 x 107J of work?
10. A new conveyor system at the local packaging plan will utilize a motor-powered mechanical arm to exert
an average force of 890 N to push large crates a distance of 12 meters in 22 seconds. Determine the
power output required of such a motor.
11. A woman runs a kilometer using a force of 210N and a power output of 500W. How long in minutes does
it take this woman to complete 1 kilometer?
12. How much power is required to raise a 5 kg object up at a constant speed of 50 m/s?