In this experiment, students will use a force sensor and friction tray to discover the relationship between the static frictional force and normal force.

• PASPORT
• 500 Interface
• 750 Interface

1. Measure the mass of the friction tray
2. Place one 500 gram mass bar in the friction tray and record the total mass of the tray and mass together.
3. Click start, then pull the force sensor and friction tray at a constant speed across the carpet.
4. Data collection will automatically start when you begin pulling and automatically stop after 1.5 seconds.
5. Repeat steps 2-3 for the three remaining mass bars. You should have a total of four data runs.
   

• DataStudio

1. What relationship exists between the static frictional force and the normal force on an object?
2. What specific equation describes this relationship? (Include numbers and units for both the slope and vertical intercept)
3. What is the physical meaning of the slope for the static frictional force-normal force graph?
4. What is the physical meaning of the vertical intercept for the static frictional force-normal force graph?
5. Scientists call the slope of the static frictional force-normal force graph the coefficient of static friction. Did the normal force on the friction tray affect this coefficient of static friction? Explain.
6. Are there other factors that might affect the coefficient of friction? Explain.
7. Optional – Repeat the data analysis, but this time produce a graph of kinetic frictional force vs. normal force. How does the coefficient of kinetic friction compare to the coefficient of static friction?