# Homework Help: Frictional Forces -- Skier trying 2 different skis on a gentle slope

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1. Oct 29, 2014

### Physisistor

1. A magazine reports that a new type of plastic ski is even more water repellent and that, on a gentle 203-m slope in the Alps, a skier reduced his time from 61 to 42 s with the new skis. Assuming a 3.0 degree slope, compute the coefficient of kinetic friction for each case.

I am having trouble just starting the problem. The time is throwing me off. Idk what equations to apply to involve this. I'm not looking for the answer but if someone could point me in the right direction that would be very helpful! thank you.

Last edited by a moderator: Oct 29, 2014
2. Oct 29, 2014

### Chrismartin33

Are you sure it's a 3.0 degree slope? That seems odd for this question..

3. Oct 29, 2014

### Staff: Mentor

Welcome to the PF.

Please re-check the PF Rules/Guidelines thread in the Feedback forum. It is very important that you fill out the Homework Help Template that you are provided, and not just delete it. You need to show us the Relevant Equations, and at least start an Attempt at the Solution.

In this problem, what are the Relevant Equations that apply? Probably at least the equation for frictional force, right? And if you draw a FBD for the skier, what is the magnitude of force due to gravity that is pointed down that gentle slope? What is the force due to gravity normal to that gentle slope?

And do you think the skier is moving with a constant velocity in each of the 2 cases, or are they likely accelerating? What does the gentleness of the slope have to do with whether they are accelerating or not?