(adsbygoogle = window.adsbygoogle || []).push({}); A problem about work

Hi! I need some help with this question:

Jim rides his skateboard down a ramp that is in the shape of a quarter circle with a radius of 5.00 meters. At the bottom of the ramp, Jim is moving at 9.00 m/s. Jim and his skateboard have a mass of 65.0 kg How much work is done by friction as the skateboard goes down the ramp?

What I used was

W=F(force) x r (displacement)

F= mv^2/r

= (65 kg x 9 m/s^2)/(5 m)

= 1035 N

W= (1035 N)(19.6 m) (To find 19.6, I used the circumference equation to find the distance down the ramp)

W= 20,286 J

20.3 kJ

I really do not think this is correct, and I'm trying to figure out what it means by "frictional" force.

Thanks for your help!

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# Homework Help: Supposed to be an easy question about WORK

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