Power cycling up a hill

Class practical

Measuring the power used in cycling uphill.

Apparatus and Materials

None listed

Health & Safety and Technical Notes

This must be done in a safe place, such as the school grounds.

Read our standard health & safety guidance

Procedure

1. Students time themselves cycling up a rise.
2. Determine the vertical distance climbed from an appropriate map or using a handheld GPS device. Alternatively, estimate the height with a sighting pole, a plumb line, and a large cardboard protractor.
3. Knowing their own weight and estimating that of their bicycle, students calculate the output of useful power.

Teaching Notes

• Useful power is calculated from:
• Useful power = energy transferred/time taken = (total weight in newtons x height rise)/time taken
• The mass of a bicycle is very unlikely to be less than 5 kg nor more than 20 kg . 10 kg would be an acceptable estimate, particularly as the mass of the student is probably of the order of 70 kg.
• This experiment could be set as a class activity if a suitable site is available.

This experiment was safety-tested in January 2006