# Energy used to ride a bicycle

1. Feb 3, 2009

### cyclebum

This is my first and probably only question on here.

Is it true that the same amount of energy is required to pedal a bicycle from point A to B, no matter the condition of the rider, or the gear ratios used, or the time it takes, as long as every thing else is equal? Weight, rolling resistance, wind resistance, etc., all equal. If not, a simple as possible explanation as to why not would be appreciated.

2. Feb 3, 2009

### mgb_phys

Neglecting air resistance and friction then it would only depend on the distance (and height difference)
However air resistance rises quickly with speed, doubling the speed gives 4x the drag force and so riding faster definitely takes more energy. Rolling resistance and friction are less dependant on speed

Last edited: Feb 3, 2009
3. Feb 3, 2009

### turin

Also, if you are interested in the amount of Calories consumed, this is dependent upon the health of the person and the condition of their muscles.

4. Feb 3, 2009

### Chuck St. Lou

Yes it's true the same amount of energy is needed. You said weight is the same so lets say the cross section is the same. Rolling resistance the same I.E. same bike. Wind resistance the same I.E. same velocity. So yes the same energy needs to be applied at the pedals. The condition of the rider? Does everybody produce work with the same efficiency and have to consume the exact same amount of fuel/food? I think that is your question. I would guess that answer is no.