Measuring coefficients of friction

Your job: measure both the static and kinetic coefficients of friction between a whiteboard and an eraser. You must turn in a report which contains

two diagrams, showing your two experiments
two tables, listing all your measurements
neat, legible calculations, showing step-by-step how to go from the measurements to the coefficients of friction
the static and kinetic coefficients of friction, each with an uncertainty
the kinetic coefficient is usually smaller than the static coefficient; does your data follow this rule?
a comparison of your results with those of at least two other groups; do the values agree within the uncertainties?

Static friction

Place an eraser on your whiteboard. Tilt the board until the eraser just starts to slip. Make at least 3 trials, measuring the critial angle each time.

What is the coefficient of static friction between eraser and board? (Hint: make a table showing all forces acting on the eraser).

Kinetic friction

Place the whiteboard flat on a table, so that it just touches the edge of the table. Place an eraser on the whiteboard so that one-third of the eraser sticks out over the edge. Mark the position of the eraser.

Now, we will give the eraser a known speed; here's how: suspend a meter stick so that it pivots at the "70 cm" mark. Arrange the meter stick vertically so that when it hangs straight down, about 10 cm of the stick extend below the eraser. Rotate the meter stick so that it is horizontal, the release it. It should swing down and strike the eraser, pushing it across the whiteboard. The speed of the eraser is just about 1 m/s.

Let the eraser skid to a halt. Measure the distance L between the starting and ending positions of the eraser.

Use the conservation of energy to figure out the size of the friction force between eraser and board; then calculate the coefficient of kinetic friction between eraser and board.