# Moment / CG question regarding a bicycle

1. Aug 17, 2006

### JohnNova

Hi,

Lets say that we have a 2 wheel bicycle riding at 2m/s. The weight distribution on this bicycle implies that the front wheel is exerting a total of 400N on the ground, whilst the back is exerting 560N.

How would I work out whether at this speed if I were to lock up the front brake, provided it didn’t skid, the rear of the bicycle would lift off the ground?

How would I work out the moment force… Where would I be measuring to… where would I define the CG (centre of gravity) to be?

I am working on an investigation and ANY help would be greatly appreciated!

Thanks in advance.

2. Aug 17, 2006

### civil_dude

You need to find the moment about the front axle, and assume a static coefficient of friction. The CG can be found by finding the equal moment the total weight produced compared to just the rear, summing them about the front.

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