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## Homework Statement

A ball is dropped and rebounds vertically to less than the original height. For this first bounce only, sketch the graph of

(a) velocity against time (2) (b) acceleration against time (2)

## Homework Equations

The solution I have for the acceleration time graph has g as -9.81 as the ball descends and -9.81 as the ball is ascending.

## The Attempt at a Solution

The graph also had velocity increasing with a uniform acceleration from zero down to its maximum value just before it hits the surface then a change of sign and it is now positive with the same velocity as just before impact. This then decreases with a uniform deceleration until the velocity reaches zero at the maximum bounce hight.

Is g always minus 9.81 because during descent it is in the negative direction in my coordinate system but accelerating, then negative for the ascent because it is in the positive direction in my coordinate system but decelerating?

In most of my SUVAT problems g was simply positive 9.81 when descending and -9.81 when ascending

any help appreciated