Torque & Levers

1. Torque & Levers Relationship between torque, force, and distance

2. torque • torque  the turning effect on a rigid object around an axis • when a force is applied and causes an object to rotate, we say that a torque was applied • the symbol for torque is Tand the units are newton-meters Nm

3. example • consider pushing a door on a hinge open • it will open easier if you push further away from the hinge • the hinge is the fulcrum in this situation (the point around which the door rotates)

4. calculating torque • 2 factors control torque: • the magnitude of the force(TαF) • the distancefrom the fulcrum (Tαd) • this gives us the formula: T = Fd • where F is perpendicular to d (at 90 degrees)

5. practice • practice problem #3 on page 83

6. torque on levers • 2 torques can be calculated for a lever: • effort torque (TE) • load torque (TL) • they can be written with the formulas: TE = FE dE and TL = FL dL

7. practice • practice problem #10 on page 84

8. law of levers • when an object is at rest, it is said to be static • an object in static equilibriumis not rotating or moving • Law of Levers  “to have static equilibrium, the effort torque must equal the load torque” • this balance results from the any clockwise torque being equal to any counterclockwise torque

9. law of levers effort torque = load toque or TE = TL or FEdE = FLdL • these equations can be rearranged to solve for any variable

10. practice • practice problem #12 on page 86