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Calculation loss of energy due to friction?

  • Thread starter okgo
  • Start date
  • #1
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Homework Statement



http://i43.tinypic.com/i1bq1i.jpg
I need help with number 9

Homework Equations



Wnet=change in KE
Wnc=Change in Energy

The Attempt at a Solution


I haven't been able to get the answer marked by the computer.
I tried Fs(h*cos15)=.5mv^2-mgh
and that is way off the anwser
 

Answers and Replies

  • #2
ideasrule
Homework Helper
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I haven't been able to get the answer marked by the computer.
I tried Fs(h*cos15)=.5mv^2-mgh
and that is way off the anwser
Can you explain that equation? I don't understand what F and s are, or how you derived Fs(h*cos15).
 
  • #3
61
0
sorry I meant that F(k) which is the force due to kinetic friction.
The equation for work is FDcos(theta). They gave use the height so I calculated the distance of the slope by Pythagorean theorem which gives cos(15)*the height.
 

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