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Physics Honors/AP 1 and 2

LAB: Investigating Inclined Plane Forces with friction

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Physics Lab

Physics Lab: Inclined Plane with Friction

Goal: to become familiar with force measurements when a non-conservative force (friction) is involved.

Materials and Equipment

Inclined Plane Setup


  1. Record your hypothesis: do you expect the static friction for a given slider to be a constant, or will it depend on the angle of the sliding surface?
  2. Weigh your slide. If you still have your equal arm scale, you can use that. If necessary, just get the weight of your slide in equivalent standard weights (e.g., 95 nickels). If you use a cup to hold your weights, you should weigh it also and include its weight along with your standard weight for total weights below.
  3. Fasten the pulley or tubing to your surface edge.
  4. Fasten the string to your slide
  5. Run the string over the edge of the tubing so that it hangs down; fasten your cup or other weight holder to the end.
  6. Start adding weights to the end of the string.
  7. Record the total amount of weight required for your slide to start moving.
  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 mass of the slide, the normal force for each trial, and the weight required to overcome static friction. Determine the static friction.
  11. Estimate errors for each of your measurements.

Data Handling

Data Reduction

Display your information appropriately in table format. Use data reduction techniques such as those outlined in the Data Handling section of the Falling Bodies lab to analyze your data.

Determine the dependence of acceleraton on the angle of inclination and the amount of friction. Is this a linear function? A non-linear function? How can you show this?

Lab Report requirements

Your report should include:

  1. A description of your equipment and procedure, in enough detail that a reasonably intelligent fellow student could repeat your experiment.
  2. Your data, arranged in tables or other format so that it is easy to read and relate values.
  3. Your error estimates for your measurments.
  4. Your conclusions.
  5. A description of your equipment and procedures which is sufficiently detailed that I could repeat your experiment myself to check your results.
  6. Your raw data and calculated data, with explanations of your asusmptions and calculations.
  7. Your conclusions about acceleration: is it constant?