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## Homework Statement

Sam, whose mass is 75 kg, straps on his skis and starts down a 50-m-high, 20 degree frictionless slope. A strong headwind exerts a horizontal force of 200 N on him as he skies.

Find his speed at the bottom of the slope using Newton's Law

Find his speed at the bottom of the slope using Energy

## Homework Equations

Conservation of Energy

F = ma

vf^2 = vi^2 + 2ad

ME_i = ME_f

## The Attempt at a Solution

I set up a drawing, found the length of the slope, did the force analysis, and got the following (Newton's Laws part):

Length of the slope = 146.19m

Force down the slope = m*g*sin(20) = 251.3848N

Force of wind up the slope = 200/cos(20) = 212.835

So Fnet = 251.3848-212.835= 38.549

a = Fnet/m = 38.549/75 = .5139

Kinematics:

vf*vf = vi*vi + 2(a)(d)

vf*vf = 0 + 2(.5139)(146.19)

vf = sqrt(150.28) = 12.25 m/s

Not sure where I went wrong.

As for the energy part, I'm not sure how to approach it.