1. J.M. Gabrielse Torque

2. J.M. Gabrielse Outline  fun with seesaws two little people a big person and a little person two little people in different spotstwo little people in different spots  equationequation  exampleexample

3. J.M. Gabrielse What Will Happen? Nothing

4. J.M. Gabrielse The Bigger Torque Wins In this case the torques are equal so they balance out.

5. J.M. Gabrielse What Will Happen? Why?

6. J.M. Gabrielse The Bigger Torque Wins The BIG FORCE creates a bigger torque than the little force. F F A force is a push or a pull.

7. J.M. Gabrielse Why? What Will Happen?

8. J.M. Gabrielse F F Both forces are the same size. The BIG DISTANCE from the pivot point creates a bigger torque than the little distance. The Bigger Torque Wins (pivot point = fulcrum)

9. J.M. Gabrielse What Will Happen?

10. J.M. Gabrielse The Bigger Torque will Win Which torque will be bigger? a little force with a BIG DISTANCE a BIG FORCE with a little distance F F

11. J.M. Gabrielse T = F d Note: d is measured perpendicular to F distance Calculate Torque (T) F pivot point d force

12. J.M. Gabrielse What Will Happen? F = 200 lb d = 10 F = 50 lb d = 70 in

13. J.M. Gabrielse Use the Equation F = 200 lb d = 10 in T = 2000 in lb F = 50 lb d = 70 in T = 3500 in lb F F

14. J.M. Gabrielse T = 2000 in lb T = 3500 in lb The Bigger Torque Wins

15. J.M. Gabrielse d2d2 d1d1 Which arm has more torque on it? Arm 1 Arm 2 F 1 = 10 lbs F 2 = 10 lbs

16. J.M. Gabrielse d2d2 d1d1 Which arm has more torque on it? Arm 1 Arm 2 F 1 = F 2 d 1 > d 2 - so - T 1 > T 2 F 1 = 10 lbs F 2 = 10 lbs

17. J.M. Gabrielse Motors Provide Torque Torque from the motor makes the wheel spin. The maximum torque from a Vex motor is 6.5 in*lb.

18. J.M. Gabrielse Motor Example How much torque would the motor need to supply? pivot point d = 15 in F = 0.225 lb motor T = F d = 0.225 lb x 15 in

19. J.M. Gabrielse Motor Example How much torque would the motor need to supply? pivot point d = 15 in F = 0.225 lb motor T = 3.375 in lb

20. J.M. Gabrielse Motor Example The motor has more than enough torque to lift a tube, but it also has to lift the weight of the arm. pivot point d = 15 in F = 0.225 lb motor

21. J.M. Gabrielse Can’t loosen a screw?

22. J.M. Gabrielse You need more TORQUE! Push harder (more force) -or- Use the long side of the allen wrench (longer distance)

23. J.M. Gabrielse Two ways to hold an Allen wrench Speed: fastTorque: low Speed: slowTorque: high

24. J.M. Gabrielse Use Torque to Tighten Screws Or your robot will end up like this!

25. J.M. Gabrielse Resources http://www.education.rec.ri.cmu.edu/roboticscurri culum/vex_online/lessons/mechanics/torque/me chanics_torque.htmlhttp://www.education.rec.ri.cmu.edu/roboticscurri culum/vex_online/lessons/mechanics/torque/me chanics_torque.html Inventor’s Guide: 3·10