Science.7
Work and the Human BodyLab 2
Inclined Planes / Name ______
Date ______
Essential Questions
  1. What is the relationship between force and motion?
  2. What does it look like when we do work?
/ Vocabulary
work, force, energy, inclined plane, simple machine, Newton, joule / Objectives
  1. Explain and investigate work, energy and force.
  2. Contrast situations where work is done with different amounts of force to situations where no work is done.

The inclined plane is a simple machine. It helps us do work by decreasing the force that we have to useto move an object through a vertical distance. There has to be a trade off, though, so we have to apply thatsmaller force for a longer distance. For example, if you lift a 20-N object through a height of 5 meters,you have done 100 J of work. The inclined plane might only require us to apply a force of 10-N tomove the same object to the same height but we would have to apply that force through a distance of 10meters (m). We are still doing 100 J of work (10-N x 10-m=100 J) but we are exerting a smaller force over a longer distance.

Some historians think that the pyramids in Egypt were built this way. The blocks of stone are huge andvery heavy. The workers may have built giant ramps of dirt to lessen the force that they would have toapply to lift the stones into place. They would have had to exert that force over a longer distance,however.

Materials:

Lab Modified from: M. Poarch – 2003

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Wooden ramps

Books

Spring scales

Meter Sticks

Lab Modified from: M. Poarch – 2003

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Remember that Work = Force x Distance.

PURPOSE/PROBLEM: Compare the way thatforce and distance change relative to each other in different inclined plane situations.

Imagine that yourgoal is to lift a textbook the height of four textbooks. In other words, the work that you are to do involveslifting a textbook the height of four textbooks, as shown below:

Pre-Lab Question:

What could be used to help you lift the book using less force?

Objective: Work with your table group to design an investigation that would allow you to determine how the length of a ramp (inclined plane) affects work, force, and motion.

Hypothesis (What is it that you are comparing, what do you think the outcome will be?)

Procedures (List the exact steps that you follow to conduct your investigation)

Draw your investigation set up:

Data Collection (Create your data table here. Hint: Be sure to include distance, force, and work)

CONCLUSION (Describe your question, hypothesis, procedures, data, and your conclusion about what you discovered. You must use COMPLETE SENTENCES).

Conclusion and Analysis

  1. If we take away the impact of friction, the same amount of work was done with and without the use of the ramp. Why is the inclined plane helpful?
  1. When we moved the books over a greater distance what happened to the force needed to move them?
  2. Longer distance equals less force needed
  3. Longer distance equals more force needed
  4. Longer distance did not affect the force needed
  1. Which inclined plane was most helpful and why?
  1. Identify some health benefits to using machines to do work.
  1. Can you identify another simple machine that makes work easier by increasing distance and reducing force?

Lab Modified from: M. Poarch – 2003

1