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**When can you assume that gravity is the only "applied force" opposing friction?**

## Homework Statement

"Determine the stopping distance for a skier moving down a slope with friction with an initial speed of 24.7 m/s. The slope makes an angle of 5.02deg above the horizontal, and assume that μk=0.172."

For this question, I have three variables that I don't have values for -- normal, mass, and acceleration. Since I only have two equations (sum of the forces for F(x) and F(y) directions), I can only have two unknowns for me to solve the problem. Am I supposed to assume that the acceleration is 9.8m/s/s (acceleration due to gravity) in this case?

## Homework Equations

Fnet = ma

## The Attempt at a Solution

Fnet(x) = n - W(x) = ma --> n - Wcos(theta) = ma

Fnet(y) = f(k) - W(y) = 0 --> f(k) - Wsin(theta) = 0

With my method of assuming that a=9.8m/s/s, I then isolated for "m" in each equation.

(1) m = n / [a +gcos(theta)]

(2) m = μ*n / [gsin(theta)]

I then equated both formulas to each other, to solve for the normal, "n".