Find the Coefficients of Friction

1. Connect a force probe to DIN 1 of the ULI. Run Logger Pro and be sure to open the Force Sensor file. You want the one set up for a single Pasco probe with the sensitivity switch set to 10 N. Adjust the graph axis to read from 0 to 1 N. You shouldn't need to change the time axis. Press the TARE button to zero the probe.

2. Lay the probe flat on the table. Start collecting data and gently tug on the probe's hook, but not so hard that you move the probe across the table. Note the graph. Now gradually increase your pull until the probe starts moving with a constant velocity. Describe what happens to the force. Find the mass of the probe and use this information to calculate the coefficients of static and kinetic friction.

3. Determine whether these coefficients depend on the force pushing the surfaces together.

4. Determine whether these coefficients depend on the area of surface contact.