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?