Quote:
Originally Posted by 8cd03gro
Hmm, maybe I'm wrong, but isn't torque = (force vector)x(displacement vector)? If there is no movement at the point at which force is applied, that means all of the force vectors have cancelled out to zero and torque can not exist. Am I wrong?
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The displacement vector is from the axis about which the force is being applied to the point which the force is being applied. Nothing requires that it actually rotates about the axis. Merely that it is drawn from that axis to the applied force. The forces can balance out, and nothing will move. But that does not mean there is no torque, just no movement.
In fact, 'static torque' is far more common in the world than 'dynamic torque' is. Usually, its refered to as a moment (particularly in structural engineering circles) but it is identical in concept to torque. Whether its a beam supporting a load, or a guy trying to get a stuck lug nut off a wheel. Nothing is moving, but there are certainly forces applied at a distance, about an axis.
You may be thinking of work or power. They require movement, but torque does not.