### High Jumping

How high can a high jumper jump? How can a high jumper jump higher without jumping higher? Read on...

### Out in Space

A space craft is ten thousand kilometres from the centre of the Earth moving away at 10 km per second. At what distance will it have half that speed?

### Dangerous Driver?

Was it possible that this dangerous driving penalty was issued in error?

# Earth Orbit

##### Stage: 5 Challenge Level:

For the first part you will need to change variables in an equation. You will need to use this idea:$$\frac{df}{dr} = \frac{df}{du}\frac{du}{dr}\;.$$ For the second part, you need to redefine your angle by shifting it by a certain amount.