Torque & Levers

Torque & LeversRelationship between torque, force, and distance

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 Nm

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)

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 = Fd

where F is perpendicular to d (at 90 degrees)

practice

practice problem #3 on page 83

torque on levers

2 torques can be calculated for a lever:1. effort torque (TE)

2. load torque (TL)

they can be written with the formulas:

TE = FE dE

and

TL = FL dL

practice

practice problem #10 on page 84

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

law of levers

effort torque = load toque

or

TE = TL

or

FEdE = FLdL

these equations can be rearranged to solve for any variable

practice

practice problem #12 on page 86