Need help finding distance of skier going down a hill! Help!

  • Thread starter Mocambo
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  • #1
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Homework Statement


A skier on a slope inclined at 4.7Degrees to the horizontal pushes on ski poles and starts down the slope. The initial speed is 2.7m/s. The coefficient of kinetic friction between skis and snow is 0.11. Determine how far the skier will slide before coming to rest.


Homework Equations


Mew(k) = F(k)/F(N)

v2^2 = v1^2 + 2a(d)

F=ma

I can't really think of others that would apply.


The Attempt at a Solution



At first I tried multiplying the initial velocity into the angle given to get :

2.7*(cos4.7) = 2.6909m/s

But I am not sure how to go from there, or even if I am on the right path here. I assume that acceleration of gravity will be 9.8m/s^2 so I could possibly get the Force through multiplying initial velocity into gravity :

(9.8)*(2.7(cos4.7)) = 26.37082 N

Help
 

Answers and Replies

  • #2
tiny-tim
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I could possibly get the Force through multiplying initial velocity into gravity

Hi mocambo! Welcome to PF! :smile:

hmm … you're getting very confused.

Think slowly and logically.

There are two forces, not one - consider each separately.

Hint: What force is pulling the skier? How much is it?

What force is stopping the skier? How much is it?

Does either of them depend on the angle?
 
  • #3
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First, you should derate the velocity due to the friction. Draw a free body diagram and that should help you out.
 
  • #4
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What force is pulling the skier : Gravitational force : 9.8m/s^2 ?

What force is stopping the skier : Force of Friction : .11 Mew(k)

Does either of them depend on the angle: I am not sure unfortunately, possibly the force pulling the skier will depend on the angle most likely .
 
  • #5
tiny-tim
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coefficient of friction

What force is stopping the skier : Force of Friction : .11 Mew(k)

(btw, if you type alt-m, it gives you "µ", instead of "Mew"!
Mew is for cats, but µ is for cool cats! :cool:)

No. µ is the coefficient of friction: that means you have to multiply it by something else. What is that?

Does either of them depend on the angle: I am not sure unfortunately, possibly the force pulling the skier will depend on the angle most likely .

Um … you need to go back to your teacher or your book and find out all about the relationship between forces and angles.
 
  • #6
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ok, well I just understood the question a little better and got the answer!!!

Thanks for all your help!
 

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