Procedure Part 2: Peak Static Friction and Kinetic Friction

In this section, you will measure the peak static friction force and the kinetic friction force as a function of the normal force on the block. In each run, you will pull the block as before, but also be changing the masses on the block (thus varying the normal force of the block)

1. Measure the mass of the wooden block on a balance and record it in your notes.

2. With no masses in the wooden, click "Start" to begin collecting data and pull as before to gather force vs. time data.

3. Determine the maximum value of the force that occurs when the block started to slide and record this into your data table. An examine button on the software will help in determining this value.

4. Highlight (with the mouse) the region of the graph corresponding to the block moving at constant velocity and select Analysis/Statistics from the menus to read the mean (average) force during the time interval. This force is the magnitude of the kinetic frictional force.

5. Repeat the experiment for two more measurements and record the values into a data table. These measurements will be averaged to obtain a more reliable value.

6. Do the experiment with different masses added to the wooden block and record the values in your data table. Note, you are repeating the experiment three times for each amount of mass added.