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Natural Science - Year I

Unit 14 Lab: Simple Machines

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Lab Assignment for Unit 14

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Natural Science Unit 14 Laboratory Activity: Simple Machines

Goal: To determine the mechanical advantage of an inclined plane

Materials and Equipment:


Inclined Plane
  1. Weigh your slide; you might use a kitchen scale.
  2. Set up the slide on the surface without the sandpaper.
  3. Fasten the string to your slide
  4. Run the string over the edge of the surface so that it hangs down; fasten your cup or other weight holder to the end.
  5. Start adding weights to the end of the string.
  6. Record the total amount of weight required for your slide to start moving.
  7. Repeat the above procedure, but this time, have the slide start on a piece of sandpaper (the sandpaper should be fastened to the surface so that it cannot move.
  8. Repeat the above procedure with another slide which has a noticeably smoother or rougher surface.
  9. Repeat the above procedure for each slide with the slide surface inclined at approximately 10° and at 15°.
  10. Make a table which shows the weight of the slide, the type of surface on which you started it, the inclination of the surface, and the weight required to overcome static friction.
  11. The weight at which the slide starts to move is a measure of the force necessary to overcome the static friction holding it back. Mechanical advantage is the ratio of load (the weight of the slide) divided by effort, or the force necessary when a machine is used (in this case, an inclined plane). Determine the mechanical advantage of each situation above. When is the mechanical advantage the greatest?


Your report should have four parts: a description of your equipment, a description of your procedure, your data, and your conclusions.