1. ## Mechanics/moments problem.

Truly stuck on this question, and not sure where the angle should be situated in the first place?

'The pedal of a bicycle is 18cm long. When it is pushed downwards by a cyclist it experiences a force of 350N. Calculate the moment when the pedal is horizontal and then when it is 65 degrees below the horizontal.'

Any help would be greatly appreciated!

2. ## Re: Mechanics/moments problem.

The moment is calculated using the cross product:

$\vec M = \vec F \ \times \ \vec R$

where $\vec F$ is the force being applied and $\vec R$ is the vector from the center of the crank to the pedal. For this problem you can calculate the cross product as simply the magnitude of F times the magnitude of R times the sine of the angle between them.