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Torque. Outline. fun with seesaws two little people a big person and a little person two little people in different spots equation example. What Will Happen?. Nothing. The Bigger Torque Wins. In this case the torques are equal so they balance out. What Will Happen?. Why?. F. F.
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Outline • fun with seesaws • two little people • a big person and a little person • two little people in different spots • equation • example
What Will Happen? Nothing
The Bigger Torque Wins In this case the torques are equal so they balance out.
What Will Happen? Why?
F F The Bigger Torque Wins A force is a push or a pull. The BIG FORCE creates a bigger torque than the little force.
What Will Happen? Why?
F F The Bigger Torque Wins Both forces are the same size. The BIG DISTANCE from the pivot point creates a bigger torque than the little distance. (pivot point = fulcrum)
a little force with a BIG DISTANCE a BIG FORCE with a little distance F F The Bigger Torque will Win Which torque will be bigger?
Calculate Torque (T) T = Fd distance force F Note:d is measured perpendicular to F d pivot point
What Will Happen? F = 200 lb d = 10 F = 50 lb d = 70 in
F F Use the Equation F = 200 lb d = 10 in T = 2000 in lb F = 50 lb d = 70 in T = 3500 in lb
The Bigger Torque Wins T = 3500 in lb T = 2000 in lb
F1 = 10 lbs 10 lbs d1 Which arm has more torque on it? Arm 2 F2 = Arm 1 d2
F1 = 10 lbs 10 lbs d1 Which arm has more torque on it? F1 = F2 d1 > d2 - so - T1 > T2 Arm 2 F2 = Arm 1 d2
Motors Provide Torque Torque from the motor makes the wheel spin. The maximum torque from a Vex motor is 6.5 in*lb.
Motor Example How much torque would the motor need to supply? d = 15 in motor pivot point F = 0.225 lb T = F d = 0.225 lb x 15 in
Motor Example How much torque would the motor need to supply? d = 15 in motor pivot point F = 0.225 lb T = 3.375 in lb
Motor Example The motor has more than enough torque to lift a tube, but it also has to lift the weight of the arm. d = 15 in motor pivot point F = 0.225 lb
You need more TORQUE! Push harder (more force)-or-Use the long side of the allen wrench (longer distance)
Two ways to hold an Allen wrench • Speed: fast Torque: low • Speed: slow Torque: high
Use Torque to Tighten Screws Or your robot will end up like this!
Resources • http://www.education.rec.ri.cmu.edu/roboticscurriculum/vex_online/lessons/mechanics/torque/mechanics_torque.html • Inventor’s Guide: 3·10