WORK & POWER

 Name:___________________________    Partner(s):________________________

___________________________________________________________________

Day _________ Time __________________

WORK & POWER

Purpose: To determine the work done and power developed by a person during walking & running up the steps.

Apparatus: foot-ruler, stop-watch, scale, and person.

Theory: Here we will look at WORK as defined below. We will assume that work only occurs when the force is sufficient to move the object. Work is a measure of what is done, not the effort applied in attempting to move the object. Work can be said to be energy in transit. Work has the same unit as energy.

    Work = Force X Distance;    Power = Work/Time;    1 horse power = 1 hp = 550 ft.lb/s.

UNITS:  

	Time	Distance	Mass	Weight	Velocity	Acceleration	Work	Power
cgs	s	cm	g	dyne	cm/s	cm/s^2	erg	erg/s
SI	s	m	kg	newton,N	m/s	m/s^2	joule,J	J/s = W
BE/USC	s	ft	slug	pound, lb	ft/s	ft/s^2	ft.lb	ft.lb/s

PROCEDURE

1. Two people need to do all the walking and running.   Choose two with different weights.

2. Walk out to the steps and measure the height of each steps, # of steps, and determine the height for one level.

3. Time the walking and running.

4. Repeat 1-3 for two levels.

5. Complete the data table.

DATA:  (Use BE/USC units)

In the table below divide each column into two for person #1 and person #2.

	One Level From !st Floor to 2^nd Floor		Two Levels From !st Floor to 3^rd Floor
	Walking	Running	Walking	Running
Weight
Height
Time
Work
Power
Horse Power

Answer the following questions:

1. Explain the unit horse power, hp including its origin.

2. Explain why there is a difference in the hp for walking and running?

3. What will happen to the hp as the person uses a large number of levels?

4. Explain why mountain roads are designed round & round, not just straight up?