Exercise 4: Understanding friction as a function of applied force

Exercise 4.1 (2 marks)

Compare your coefficient of static friction (µs) and kinetic friction (µk), which one is bigger? Does this make sense? Explain why or why not in 2-3 sentences.

Use the form below to submit your values of mu to add to the class data set. We are interested to see the distribution of values obtained by students taking Physics 1A03, there are no ‘right’ or ‘wrong’ answers.

Exercise 4.2 (1 mark)

The graph below shows the force of friction as a function of applied force for a shoe on a ramp. For the scenario where the applied force increases steadily from zero; moving left to right along the x-axis, describe what is happening in region 1 and region 2. Pick the correct option directly on Crowdmark.

Force of friction as a function of the applied force. In region one the force of friction is equal to the applied force. In region 2 the force of friction is constant after dropping down from a maximum value.

Exercise 4.3 (1 mark)

Now imagine that you do the same experiment (scenario where the applied force is increasing; moving from left to right along the plot) with “Shoe B” which has the same friction coefficients but is half the mass as “Shoe A”. In the graph below we can see “Shoe A” is the solid pink curve. Which curve represents the friction as a function of applied force for “Shoe B”? Pick the correct option directly on Crowdmark.
A graph of the force of friction as a function of the applied force with 5 different curves. The solid pink line shows Shoe A. The solid red line shows a curve with the same shape as shoe A, but half the max friction. The green dashed curve has a different slope initially, greater than shoe A. The blue solid line is the same shape as shoe A with 1/4 the max friction. the black dashed line has a different shape with a more shallow slope initially.

Before you continue!

Before continuing, be sure you have completed (4.1), (4.2), and (4.3), which will be graded and submitted through Crowdmark.

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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.