- #1

gcfve

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## Homework Statement

1. Homework Statement

A particle of mass m moves under action of a repulsive central force Fr=Cr-3 with constant C greater than 0. At a very large distance from the centre of the force, the partcle has kinetic energy K and its impact parameter is b. Use conservation of energy and angular momentum to show that the closest m comes to the centre of force is rmin=[tex]\sqrt{b^2+ C/2K}[/tex]

2. Homework Equations

L=mbv0

E=.5mvr2+L2/2mr2+V(r)

3. The Attempt at a Solution

So far, I said that since the object is far away its total energy is K

I think V(r) = -3C/r2, but I'm not sure.

And at rmin, E==.5mvrmin2+(mbv)2/2mr2-3C/rmin2

I don't know what to do next.