Jeopardy! category: MAY THE FORCE BE WITH YOU (04-11-2015)
$1600 clue: Take a second to turn things over & identify this, also called the moment of force
The gist: There’s a twist to this clue. Torque is defined as the tendency of a force to rotate a body about a point. Just as pushing a body tends to cause it to go straight (barring any obstacles), “torquing” an object tends to make it rotate. Everyday examples of applying torque include turning a screwdriver (which rotates the screw around its central axis) and a car engine (which rotates the crankshaft using the force generated by its pistons), but any example of a force rotating something involves torque – even two kids on a seesaw jumping up and down rotates the board around the fulcrum.
Torque is measured either in pound-inches or pound-feet, or in the more scientific units of Newton-metres (Newton being the SI unit of force). It’s usually represented as a tau (a Greek T), and is calculated as rF(sin(θ)), where r is the distance between the body and the point of rotation (i.e. the radius of the circle on whose circumference the body is traveling), F is force applied, and θ (theta) is the angle between F and r (so if you tried to apply the force at the same angle as the torque, you wouldn’t accomplish much – imagine trying to screw in a screw with the screwdriver perpendicular to it).
The clue: The “turn things over” is clearly a sly reference to torque, but without knowing what the moment of force is (it’s what the Brits call it), it could hint at any number of things (I would have guessed “rotation” were I forced to). Contestant Jenny guessed “impact,” unfortunately, I guess mistaking the “moment of force” for a moment in time.
In Jeopardy!: A search of “torque” in the J!Archive returns 36 clues, but a full half of them are actually about Tomás de Torquemada, the first Grand Inquisitor of the Spanish Inquisition, who used force in very different ways (and may indeed have taken advantage of torque in his own way). Most of the clues that are about our torque mention something like rotation, or, turning, or twisting. The rest are about certain mechanical parts, like torque converters and flywheels (which are a type of torque converter). Usually, a physics clue about twisting or turning is talking about torque, but by no means always.