Fall 2006 Name______________

Measure your
Horsepower

This page is your pre-lab. All of this page is to be completed before
you arrive in class. This material is
covered on pages 64-66 in your text.

Define Work:

What is the relationship between the force
and the direction of the motion in the above definition?

What are the units of work?
_______________________

Write the definition of a joule in terms of
newtons and meters.

Define power:

What are the units in which power is
measured? ___________________

Write the definition of a watt in terms of
joules and seconds.

Calculate the work done if an 85 kg person
climbs vertically 6 meters. Clearly show
each step in the solution.

How does this work change if the climbing
is done at a 45-degree angle, but the total vertical movement remains 5
meters? Explain your answer!

If it takes the person 10 seconds to climb
the 6 m in the previous problem, what is the person's power? Show your work clearly.

How many horsepower is this? (Note: 1 horsepower
is 746 watts)

Clearly show your work!

What
is your weight in pounds? _________________________

Note:
There are 2.21 lbs/kg

Convert
the above to give your mass in kilograms_____________________

ALL
OF THIS FIRST PAGE IS TO BE COMPLETED BEFORE COMING TO LAB!

In
Lab

Calculate
the amount of work __you__ would do if you climbed stairs that were 10
meters high. Clearly show how you arrive
at your answer!

Have
the instructor check your answer before proceeding. ______

If
the weather is good, do the following outside on the football stadium,
otherwise use the stairs from the basement of the

Determine
the average height of one step. To do
this measure every 4 steps, write the results on the side of this page, then
average your results to obtain the average height of a step:________ (in
meters)

How
many steps are there? ______________

Calculate
the total vertical rise of all the steps (number of steps________ times the
height of one step_________: = ___________ m

Measure
the amount of time necessary for you to climb the stairs. You have the choice of doing this at your
maximum speed to calculate your maximum horsepower, or you may move up them at
your normal pace and calculate your normal power output. Repeat this two times and use the average in
your calculations.

Time
1 = _________ Time 2 = _________ Average time = __________

Calculate
the work done: Clearly show each step in the calculation. If you need assistance, speak with the
instructor.

Work done by climbing the stairs =

Calculate
the power:

Power =

Convert
your answer to horsepower: (See front page!)

Horsepower =

Have
the instructor check your work. _______

The
instructor will indicate a number of books to you that are to be placed in 3
equal stacks beside one of the lab tables.
He will indicate to you the mass of the books. Mass of books = _____________

Vertical
distance books are moved? (Height of table.) h = ____________

Now
have someone time you as you lift the books onto the table.

time
= _____________

Calculate
the total work done. Clearly show your work!

Work
done in lifting the books onto the table =

Data Formula
Work

Calculate
the power: Clearly show your work!

Data Formula
Work

Convert
to horsepower:

If
you maintained this output for one hour, how many kilowatt-hours of work would
you have done? ____________________________

Have
the instructor verify your answers above _____

In
Marshall, the cost of energy is less than 8 cents per kilowatt-hour. If you worked for the same wage at the same
pace ($0.08/kwh), calculate what your hourly wage would be. Clearly show your work. Write your answer
below:

Amount I would
receive for an hour’s work =

Calculate
what your pay for a 40-hour week would be. Write your answer below:

(1) Amount I would be paid for 40 hours work =

Have
the instructor verify your answer _____

If
you worked at this pace for 40 hours, how many kg of books could you put on the
table? Hint: Calculate how many books you would put on the table in one minute,
and then multiply by the number of minutes in 40 hours.

___________________

(2) How much would electricity cost to run a
conveyor belt that did the same amount of work? ____________________

(Note
that you have already done this calculation in point (1) above!)

If you hired a
person to do this work and paid them $8.00 per hour for the 40 hours, what
would they receive for this hard work? _________

Yet if you had an
electric motor to do the same amount of work the cost would be your answer to
(2) above. How much more do you pay the
person than it would cost to use an electric motor to do the work? Express your answer as a whole number, 4
times as much, etc.