Torque

Center of Gravity The point at which all the weight is considered to be concentrated The point at which an object can be lifted w/o producing rotation

Center of Gravity In asymmetric objects, the center of gravity may not be the geometric center

Translational Equilibrium Occurs when an object is not accelerating

Rotational Equilibrium Occurs when an object is not rotating or the rotation is uniform

Torque The rotational effect of an object produced by a net force that is not applied to the center of gravity

C = Pivot Point or Center of rotation FT A B C Torque arm Torque arm WA C = Pivot Point or Center of rotation WB

Pivot Point Reference point from which to measure rotational forces

Torque Arm The length between the pivot point and the point where a force is applied

Torque The product of the applied force and the length of its torque arm:

6 m 4 m TorqueA = WA x 6 m TorqueB = WB x 4 m FT Torque arm Torque arm C TorqueA = WA x 6 m TorqueB = WB x 4 m WA WB

A TorqueA = WAAcosa TorqueB = WBBcosb FT B WB WA Torque Arm A Torque Arm B A TorqueA = WAAcosa TorqueB = WBBcosb WA

FN = FA sin a FN FA a a l sin a Torque =FAl sin a

Calculate the torque on a 250 cm rod with a pivot point at one end and a 500.0 g object sitting on the other end

A person ties a rope to one end of a 10 A person ties a rope to one end of a 10.0 m I-beam & tries lift it by pulling with 2500 N at 37o from horizontal