1. Trolley Friction Lab PURPOSE: To measure the coefficient of kinetic friction of the trolley rolling along the cable using (1) a free-body analysis of the forces acting on the trolley, and (2) kinematic data from the movement of the trolley. The final analysis will require combining the separate results from the trolley rolling up the cable and rolling down the cable.

2. SET-UP: 3.000 m buret stand camera wire cable 3.000 m Top View Side View towel Trolley Friction Lab

3. DATA COLLECTION PROCEDURE:  Hang a 200 g mass from the trolley  Hang the trolley on the wire, about a meter to the right of the right-hand buret stand  Start the video camera and push the trolley up the cable, being sure you release it before it reaches the first buret stand.  You need to push the trolley hard enough that it just passes the left hand stand, but not so hard that it wobbles all over the place. A smooth push and release is essential. You may have to practice several times!  Download the video to your laptop Trolley Friction Lab

4. DATA COLLECTION:  Upload the video, resize it, and set the scale and origin; as in the previous trolley lab.  Collect separate sets of place data for the uphill and downhill movements of the trolley.  Use Logger Pro to calculate the acceleration of the trolley both uphill and downhill (a up and a dn ). Trolley Friction Lab

5. ANALYSIS:  Construct FBDs for both the uphill and downhill phases of motion.  Use the diagrams and NL2 to figure out expressions for the uphill and downhill accelerations in terms of: acceleration due to gravity g mass of trolley m (although this will vanish) angle of cable θ coefficient of kinetic friction μ K of the trolley  Use these two expressions and your measured accelerations to calculate a value for both g and μ K. Trolley Friction Lab

6. REPORT: Your team will complete a full lab report for this lab using the Google Docs template titled “Physics Lab Report Outline”. All members of the team are expected to contribute about equally to the process (the document history will be checked), and the final report should be shared with Dr. V with editorial privileges. Trolley Friction Lab