Sept-18-2014 Determining coefficients of static and kinetic friction on a sloped surface

Purpose:

Students will determine the static and kinetic friction coefficient of a block on a sloped surface.

Lab:

The students used a metal track to provide a sloped surface.

Setup:

The students then placed a wooden block on the ramp and adjusted the height of track to the point where the block just starts to move. This would allow the students to calculate the static friction coefficient.

The students then measured the height and length of the track and using the pythagorean theorem found the angle of the track.

With this information the students followed the problem solving steps in physics and created a Free Body Diagram and determined the forces acting on the block. Through these calculations, the students found the static friction coefficient.

Calculations:

The students calculated the static friction coefficient to be 0.3.

The students used the same setup to find the kinetic friction coefficient.
The students raised the ramp this time allowing the block to slide freely over it. Then the students used a motion sensor to record the blocks velocity vs time. The students determined the slope of the graph would be the acceleration.

Graph:

The students also measured the height and length of the ramp to find the angle of the ramp.
With this data the students then drew a new Free body diagram and used it to calculate the kinetic friction coefficient.

Calculations:

The students found the coefficient of kinetic friction to be 0.386.


Conclusion:

The students were able to utilize their knowledge of physics to determine the coefficient of static and kinetic friction with experimental data. Lab success.