Kinetic Friction and skis thrust

AI Thread Summary
The discussion revolves around calculating the forces acting on Sam as he descends a slope on jet-powered skis. Key forces include the thrust from the skis, gravitational components, and friction. The user has calculated the gravitational force and its components, determining the normal force and the net force acting down the slope. There is uncertainty about the next steps, particularly whether the problem is asking for the coefficient of friction. Clarification on the problem's requirements is sought to proceed with the solution.
BlakeGriffin
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Homework Statement


Sam, whose mass is 71.0 kg , takes off down a 51.0 m high, 11.0 degree slope on his jet-powered skis. The skis have a thrust of 210 N . Sam's speed at the bottom is 41.0 m/s .


Homework Equations


I'm not sure which equation(s) to use.
Net Force= ma and some kinematic equations maybe?


The Attempt at a Solution


This is the free body diagram that I came up with.
http://img291.imageshack.us/i/fbdy.jpg/ (It's not to scale)
There is also the thrust force coming from the skis in the opposite direction of the friction force. I couldn't fit them all in. Btw the dashed lines are the components of the gravity force.

If my free body diagram is right, then normal force = FG Cos(theta) which is one of the components of the gravity force. The other component of gravity is FG Sin(theta)

FG is mg = (71 KG)(9.8 m/s^2)=695.8 N
FN=FG Cos(theta)=695.8(cos(11))0=683N
The other component of FG is =FGSin(theta)=695.8(Sin(11))=133N

Since this component of gravity and the thrust force coming from the skis both point down the hill (or whatever) I get 133+210=343N pointing in that direction.

I don't know where to go from here.. Can anyone help me?
 
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Ummm...what's the problem asking? Is it looking for the coefficient of friction or something?
 
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