- #1

Cbray

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## Homework Statement

A particle moves in a straight line away from a fixed point O in the line, such that when its distance from O is x its speed v is given by v=k/x , for some constant k.

(a) show that the particle has a retardation which is inversely proportional to x

^{3}

The answer is

**-k**

^{2}*x^{-3}(b) if a,b,c,d are points in that order on the straight line, such that the distances ab, bc, cd are all equal, show that the times taken to travel these successive distances increase in arithmetic progression.

## Homework Equations

Possible the answer to the first one comes into relevance, -k

^{2}*x

^{-3}

## The Attempt at a Solution

let the four points have x coordinates

x, x+x

_{o}, x+2x

_{o}, x+3x

_{o}

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