### Lunar Leaper

Gravity on the Moon is about 1/6th that on the Earth. A pole-vaulter 2 metres tall can clear a 5 metres pole on the Earth. How high a pole could he clear on the Moon?

### High Jumping

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

### Escape from Planet Earth

How fast would you have to throw a ball upwards so that it would never land?

# Slingshot

##### Stage: 5 Challenge Level:

If a projectile is fired at an angle of 45° to the horizontal then the initial speed of the projectile and the distance it travels is related by $d = \frac{v^2}{g}$.

Use the conservation of energy in order to find the speed of the stone. The energy stored in a strip which is extended by $\delta x$ is equal $E = \frac{k \delta x^2}{2}$.