(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

2. Relevant equations

W = Fk d cos θ

Fk = FN μκ

3. The attempt at a solution

Here's my work :

m = 1 kg vi = 10 m/s vf = 0 m/s xi = 0 m xf = 0.1 m d = 0.1 m k=60 N/m μκ=?

The work done be the frictional force :

W = Fκ d cos θ = FN*μκ*d*cosθ = mg μκ d cos 180 = - 0.1*10*1 *μκ = - μκ

- μκ = W = ΔKE + ΔUg + ΔUs

ΔUg = 0 , because the height doesn't change

- μκ = 0.5 m vf^2 - 0.5 m vi^2 + 0.5 k ( xf )^2 - 0.5 k ( xi )^2

- μκ = 0 - 0.5 * 1 * 10^2 + 0.5 * 60 *( 0.1 )^2 - 0

- μκ = - 49.7

μκ = 49.7

I don't know why I've got unreasonable answer . Could somebody help me to solve this problem ?

Thanks for your help

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# Homework Help: How to get the coefficient of kinetic friction?

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