1. Coefficient of Friction Pre-lab Purpose –Determine the coefficient of static friction. –Determine the coefficient of sliding friction. Materials –Force scale, wood crate, masses (100 g, (2) 200 g, 500 g, 1 kg) Procedure – your procedure should be detailed on how to do each step. –Calculate F N –Measure F A required for static and sliding (same as F f ) –Repeat with next mass increment (100g increments to 1 kg)

2. Coefficient of Friction Pre-lab (cont) Data Table (2 – one for static and one for sliding) Mass (kg) Normal Force - F N (N) Applied Force - F A (N) Frictional Force - F F (N) 0 0.100 0.200 … 1.000

3. Coefficient of Friction Pre-lab (III) Graphs (2) –F N vs F f (Your graphs will be linear. Make sure they go through the origin and calculate the slope.) Conclusion Questions 1.Explain what the coefficient of friction means. 2.Explain how you know F A and F f are the same amount. 3.In calculating the slopes of your graphs you have calculated µ. Explain how you know this. 4.Compare µ static to µ sliding. Which is bigger? Is this what you expected? Explain.

4. Lab Notes Make your procedure as detailed as possible. Show, label and organize all calculations. Slope calculations can be shown on graph. Each graph should be a full sheet of paper and done with a straightedge. Neatness is worth points on this lab.