Torque

Torque applied via anadjustable end wrench

Relationship between force, torque, andmomentumvectors in a rotating system

Inphysics,torqueis the tendency of aforceto turn or twist. If a force is used to begin tospinanobject,or to stop an object from spinning, a torque is made.

The force applied to alever,multiplied by thedistancefrom the lever'sfulcrum,multiplied again by thesineof the angle created, is described as torque. This is also known as "rcrossf, "or" force times fulcrum distance times sine theta. "

Fulcrum

Fulcrum is theaxisofrotationor point of support on which a lever turns in raising or moving something.

Equation

Theequationfor torque is:

${\boldsymbol {\tau }}=\mathbf {r} \times \mathbf {F} \,\!$

whereFis the net forcevectorandris the vector from the axis of rotation to the point where the force is acting. TheGreek letterTauis used to represent torque.

The units of torque are force multiplied by distance.The SI unit of torque is thenewton-metre.The most common English unit is thefoot-pound.

Other websites

• "Horsepower and Torque"Archived2007-03-28 at theWayback MachineAn article showing how power, torque, and gearing affect a vehicle's performance.
• a discussion of torque and angular momentum in an online textbookArchived2010-12-14 at theWayback Machine
• Torque and Angular Momentum in Circular MotiononProject PHYSNET.
• An interactive simulation of torque