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

A skier moving at 5.00 m/s encounters a long, rough horizontal patch of snow having coefficient of kinetic friction 0.220 with her skis. the patch is 2.9 meters long.

what is her velocity after passing the patch?

problem must be solved by using work, avoid newtons

2. Relevant equations

work = fs

work = [tex]K_{final} - K_{initial} =- \frac{1}{2}m v^{2}_{final}- \frac{1}{2}m v^{2}_{initial}[/tex]

3. The attempt at a solution

let s be displacement (2.9m)

[tex] -\mu_{k}mg*s = - \frac{1}{2}m v^{2}_{final}- \frac{1}{2} m v^{2}_{initial}

[/tex]

m is irrelevant, factor it out and cancel.

[tex]

-\mu_{k}g*s = - \frac{1}{2} v^{2}_{final}- \frac{1}{2} v^{2}_{initial}[/tex]

solve for [tex] v_{final} [/tex]

[tex]\frac{-\mu_{k}gs+.5v^{2}_{initial}}{-.5} = v^{2}_{final}

[/tex]

[tex]

\sqrt{-2(-\mu_{k}gs+\frac{1}{2}v^{2}_{initial})} = v_{final}

[/tex]

[tex]

\sqrt{ -12.4952}

[/tex]

cannot take sqrt of negative number.

i can't go beyond this part, is there a solution?

**Physics Forums | Science Articles, Homework Help, Discussion**

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Work and velocity problem

**Physics Forums | Science Articles, Homework Help, Discussion**