- #1

bobie

Gold Member

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## Homework Statement

This is not homework. Suppose I am rotating a ball on a string (m=1, r = .2, v = 10 m/s)

## Homework Equations

F

_{c}= (m) v

^{2}/r = 500 N*m

If I reduce the length of the string to .1, v becomes 20, so

F

_{c}= 4000 N*m

what is the work I have done, what kind of integration do I need,

does the energy spent depend on the speed/time I use to pull the string?

Thanks for your help