Physics LabWork and Power: What’s your Horsepower?

Name: ______Name: ______Date: ______

Name: ______Name: ______Block: ______

Background:
Automobile engines are rated by their horsepower (hp) in the U.S. In countries that use the SI system, they are rated in kilowatts (kW). What is your horsepower? How many kW do you generate? We will determine the power generated while climbing stairs.

For purposes of this lab, work done is against Earth’s gravity. The work to start moving in the horizontal direction is ignored. Any motion in the horizontal direction is irrelevant (θ = 90o)

Recall:

Work = force * distance, and is measured in Newton-meters, or Joules.

Power =work per unit time, a rate, and is measured in Joules/second, or Watts.

1000 W = I kW = 1.34 hp

Mass (kg) = Mass (lb) / 2.2

Weight (N) = Mass (kg) x 9.8 m/sec2 (W = mg)

Equipment needed for each group:

  • Tape measure
  • Bleachers (good weather) or stairway (bad weather).
  • Timer
  • Weighing Scale

Experimental Procedure:

You and your lab partners will calculate the power (in hp, W, and kW) during a stair climbing activity for two or more members of the lab group. If a member does not climb stairs, he or she should be timing or writing down results.

Using what you know about work and power, devise an experiment to calculate power generated while remaining at a safe speed and climbing stairwell or bleacher stairs. You may use the equipment listed above. Stretch out and limber up as needed! Do not pull a hamstring!

For each climber, do three (3)trials. Later, we will average your results to determine final answers.

Grading:

  1. Accuracy counts! Measure and calculate carefully. Always use correct units.
    Answers should “make sense,” and you, for example, should not find yourself to possess 100 hp.
  2. Sloppy labs will be shredded.
  3. No HORSEPLAY during Horsepower lab

Team member # 1 walking slowly up the stairs

Mass (kg) / Weight = m.g
(N) / Height of stairs
(m) / P.E = Weight × Height (J) / Time (sec) / Power (W)
/ Power (kW) / Power
(HP)

Team member # 1 running up the stairs

Mass (kg) / Weight = m.g
(N) / Height of stairs
(m) / P.E = Weight × Height (J) / Time (sec) / Power (W)
/ Power (kW) / Power
(HP)

Team member # 2 walking slowly up the stairs

Mass (kg) / Weight = m.g
(N) / Height of stairs
(m) / P.E = Weight × Height (J) / Time (sec) / Power (W)
/ Power (kW) / Power
(HP)

Team member # 2 running up the stairs

Mass (kg) / Weight = m.g
(N) / Height of stairs
(m) / P.E = Weight × Height (J) / Time (sec) / Power (W)
/ Power (kW) / Power
(HP)

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