Exercise 3: Measuring coefficient of kinetic friction

In the next part of this lab you increase the angle of your ramp only slightly higher than the angle you found in Exercise 2 ; ~3-5 degrees. This will let you determine the coefficient of kinetic friction, 𝝁k.

 

Procedure:

(see below video for extra guidance if needed)

Set up your shoe and ramp like you did in Exercise 2.

Pick an angle that you will do your kinetic friction experiment at. We recommend an angle only slightly larger than the angle found in exercise 2; ~2-4 degrees more.

Place your shoe at the top of your ramp and measure the length the shoe will slide. This should be from the toe of your shoe to the edge of the ramp as shown in the image below. The longer the ramp the more accurate your results will be.

In the lab:

At home:

shoe placed on a cardboard ramp with a measuring tape measuring the distance from the toe of the shoe to the bottom of the ramp.

Release your shoe from the top of the ramp and time how long it takes to slide to the end.

Repeat the above three steps two more times and record the angle, length of ramp, and time in the kinetic friction results table. Note: Leave the coefficient of kinetic friction (𝝁k) and acceleration (a) columns blank for now, you will be calculating both in the next section.

In the lab:


At home:

 

Exercise 3.1 (1 mark)

Submit a photograph of your experimental set-up showing how you made these measurements with your shoe (or calculator) and your ramp.

 

Results
Coefficient of Kinetic Friction Data (excel file for kinetic friction results table)

Angle of ramp

Length of ramp

Time to slide down ramp

Acceleration of shoe

Coefficient of kinetic friction

Trial #
θ

[°]

d

[m]

t

[s]

a

[m/s2]

𝝁k

[1]

1

2

3

Average

Analysis

Exercise 3.2 (1 mark)

Use kinematics to find the acceleration of the shoe during each of the three trials. Remember that you know three variables – the shoe was released from rest, and it travels a distance d m down the ramp in t s. We assume the acceleration is constant. Show a calculation for the acceleration for one of the trials. Remember to include units and define down the ramp as the positive x-direction.

Exercise 3.3 (1 mark)

Use the acceleration you calculated in (3.2) along with the equation from (1.4) to calculate 𝝁k. Show a calculation for the 𝝁k for one of the trials.

Exercise 3.4 (2 marks)

Submit a copy of your completed chart (template available here). 

Before you continue!

Before continuing, be sure you have completed (3.1) to (3.4), which will be graded and submitted through Crowdmark.

 

License

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Physics 1A03 - Laboratory Experiments Copyright © by Physics 1A03 Team is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, except where otherwise noted.