Torque and Chrome

Need help finding equation for torque?

I have a bike with a weight of five pounds tied to the rim. I use a torque wrench to turn the bolt at the center of the pedal (which turns the wheel). The resistance will always be a constant five pounds, so the distance turned is irrelevant. believe me, I actually got a torque wrench and tested it, and the torque stayed the same no matter how much it was turned. Basically, think of it as a screw that always had a five-pound resistance, and if it was held still, there would always be five pounds of force pulling it, so how much torque would be required to keep it from turning? (i need an equation to determine this. the answer is about 60 pound-inches.) the force is applied to the exact center. I used a torque wrench, which should be calibrated to remove the length of the handle.

Public Comments

1. That is probably because your wheel's radius is 12 inches. There is a standard formula for torque, which is a CROSS PRODUCT in its full form. tau = r cross F Cross the radius vector (from origin to force application point) with the force vector, and get the torque vector. What the cross product does, is multiply the two vector magnitudes by each other, and then by a factor of "perpendicularity". If the radius vector and force vector are perpendicular, the "factor of perpendicularity" is one. If they are aligned, then the factor of perpendicularity is zero. The resulting magnitude of the torque vector is CONSIDERED TO BE in the direction of the axis of the rotation it would cause, and set-up so it matches the right hand rule. Of course, for our purposes, we don't care about direction, and we don't care about perpendicularity since it is equal to one anyway. All we care about is that torque equals the product of the force and the radial coordinate of where it is applied.