TORQUE

SECOND POST

DEFINITION OF TORQUE

• Tendency of an object to change or cause rotational motion.
• The torque depends on F ( force ) applied and r ( distance between of the rotation axis and the point of the force ).In symbols :

                                                                       τ  : The torque.

                                                                       r  : The displacement from rotation axis to point of the force.

                                                                       F : The force.

• We know F is equal to m ( mass ) multiple by a ( acceleration ).

                                                                      F = ma

• Direction of torque :

                             = Positive if counterclockwise ( + )

                             = Negative if clockwise ( - )

QUESTION

At the figure, give two lever with the same length and force. But, the displacement from rotation axis to point of force is difference. Use the formula and find which of the lever can be applied for the wrench.

                          LEVER A                            LEVER B                                               

                           r     : 10 m                             r    : 6 m

                           F    : 5.6 N                           F    : 5.6 N

CALCULATION

        LEVER A                                LEVER B

           τ = Fr                                    τ = Fr
           τ = ( -5.6 ) ( 10 )                    τ = ( -5.6 ) ( 6 )

           τ = -56 Nm                            τ = -33.6 Nm

                             

• The force is negative because the rotation is clock wise.

From the answer,we get that Lever A have large torque and Lever B have a smaller torque,so lever A better to be applied because it have a higher Torque.So,the force used to turn the lever is low. Torque can be change if the force ( F ) or displacement ( r ) transformed.The direction of rotation should also be checked whether clockwise or counter-clockwise.If the displacement ( r ) is given in units of cm, it must be converted to unit m, this is because SI Unit of torque is newton meter ( Nm).

• Torque ( τ ) is a measure of the turning force ( F ).
• Just as a force ( F ) is a push or a pull, a torque can be thought of as a twist.
• Where force ( F ) tells us how hard we are pushing or pulling on something, torque ( τ ) indicates how hard we are twisting on it.
• High Torque - Low Force
• Low Torque - High Force