A little assistance with Friction mu k

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SUMMARY

The discussion focuses on calculating the coefficient of kinetic friction (µk) for a skier who comes to rest after skiing down a frictionless slope. The skier, with a mass of 62 kg, reaches a speed of 26.7 m/s at the bottom of a 69 m slope inclined at 32°. The skier then travels 160 m on a horizontal path before stopping. The key equations utilized include Newton's second law and the relationship between frictional force and normal force, leading to the conclusion that the coefficient of kinetic friction can be derived from the skier's deceleration and the normal force acting on them.

PREREQUISITES
  • Understanding of Newton's second law of motion
  • Knowledge of frictional forces and coefficients
  • Basic trigonometry for resolving forces
  • Familiarity with kinematic equations
NEXT STEPS
  • Calculate the acceleration of the skier on the horizontal surface using kinematic equations.
  • Learn how to derive the normal force acting on an object on a horizontal surface.
  • Study the relationship between frictional force and acceleration in detail.
  • Explore examples of kinetic friction calculations in physics problems.
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Students studying physics, particularly those focusing on mechanics and friction, as well as educators looking for practical examples of applying Newton's laws in real-world scenarios.

tducote
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Homework Statement


A skier with a mass of 62 kg starts from rest and skis down an icy (frictionless) slope that has a length of 69 m at an angle of 32° with respect to the horizontal. At the bottom of the slope, the path levels out and becomes horizontal, the snow becomes less icy, and the skier begins to slow down, coming to rest in a distance of 160 m along the horizontal path.

a) What is the speed of the skier at the bottom of the slope?
m/s
i solved a) and got that it was 26.7 m/s for the speed

B is what i am having trouble with
b) What is the coefficient of kinetic friction between the skier and the horizontal surface?
µk =


Homework Equations


fmax= mu k N i think



The Attempt at a Solution



I tried many different ways...
26.7/607.6 = uk .04
uk mgcos(theta) = ma
uk 62(9.8cos32) = (5.19)(62) = .6 ... something

I am still confused about how to solve this any hints or techniques would greatly be appreciated

P.S. this is my first post please be kind :)
 
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tducote said:
fmax= mu k N i think
Close enough: f_k = mu_k N (No need for max--you were thinking of static friction.)

Hint: The frictioned section of the path is horizontal.

What's the skier's acceleration?
What's the only horizontal force acting on the skier?
Apply Newton's 2nd law and solve for mu_k. (What's N?)
 

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