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## Homework Statement

A mass moves in a circular path that has a radius of 24.6cm on a horizontal frictionaless surface. If the centripetal force acting on the mass is 96.5N, what is the kinetic energy of the mass?

r=0.246m

F

_{c}=96.5N

## Homework Equations

He told us to use these and "play around with them":

F

_{c}=mv

^{2}/r

E

_{k}=0.5mv

^{2}

## The Attempt at a Solution

I have not a clue as to how to even begin this one. Maybe use the idea that acceleration centripetal=force centripetal(minus mass)? So use:

a

_{c}=v

^{2}/r

96.5N=v

^{2}/0.246m

v

^{2}=392m/s

v=19.8m/s

F

_{c}=mv

^{2}/r

96.5N(0.246m)=m(19.8m/s)

^{2}

m=0.0605kg

E

_{k}=0.5mv

^{2}

E

_{k}=0.5(0,0605kg)(392m^2/s^2)

E

_{k}=11.9J

Or am I completely and irrevocably lost?