### 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?

### Wobbler

A cone is glued to a hemisphere. When you place it on a table in what position does it come to rest?

### Bridge Builder

In this short problem we investigate the tensions and compressions in a framework made from springs and ropes.

# More Bridge Building

##### Stage: 5 Challenge Level:

Clearly the bridge will be pulling down on the supports so they will be exerting an upwards reaction force on their supporting pin joints. What does the direction of the reaction force tell us about the forces in the diagaonal support? What does this imply about the direction of the forces in the next strut?

Once you have understood the principles which allow you to determine the locations of tensions and compressions in the bridges you should be able to fill in a picture of tensions and compressions without the need for any numerical calculations.