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 T and 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: 1. the magnitude of the force (TαF) 2. the distance from 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: 1. effort torque (T E ) 2. load torque (T L )  they can be written with the formulas: T E = F E  d E and T L = F L  d L

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 equilibrium is 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 T E = T L or F E  d E = F L  d L  these equations can be rearranged to solve for any variable

10. practice  practice problem #12 on page 86