Physics Core/AP 1 and 2

Physics Lab

# Lab: Inclined Plane

## Goal: To determine the magnitude of forces on a block on an inclined plane.

#### Materials and Equipment

• an elevated surface on which you can slide things with as little friction as possible: a glass or very smooth metal surface is good. A flat sheet of ice down which you can slide ice cubes or smooth metal or plastic cubes is ideal, but more difficult to create.
• a pulley you can clamp to the edge of your surface. If you can't find a pulley, reduce the friction at the edge by using a roll of plastic tubing along the edge.
• several sliders: They should have flat surfaces where they will be in contact with the support surface and be as smooth as possible.
• pins, tape, or other means of fastening string to your slider.
• string
• a set of standard weights (I like using coins; try to weed out any that are too worn). These do not have to be any particular unit, but they should all be the same.
• a bucket, sack, or other means of keeping the weights together.
• blocks or other means of inclining your slide surface
• stop watch
• protractor

#### Procedure

1. Record your hypothesis: how will acceleration 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. Time the drop if you can.
9. Repeat the above procedure for each slide with the slide surface inclined at 2-5 degree intervals for high slope (a low slope may allow your mass to accelerate too quickly to measure differences in drop rates).
10. Make a table which shows the mass of the slide, he weight required to overcome static friction, the angle of the incline, and the drop time.
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. Is this a linear function? A non-linear function? How can you show this?