- #1

rsala

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## Homework Statement

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

## Homework Equations

work = fs

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

## 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?

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