Download - 4. Force System - Moment
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MOMENTBy Rani Rumita
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• The Moment of a Force also known as the torque (T),is dened as the force F acting at a perpendiculardistance d, and causes an o!ect to rotate
• Tendency of the force to rotate the ody aout the
a"is
• The asic units of
moment in #$ units are
%ewton&meters (%'m),
and in the '#'
customary system are
ound&feet (l&ft)
Moment (M)
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Magnitude of Moment
The magnitude of themoment or tendency of theforce to rotate the odyaout the a"is *&*
perpendicular to the plane ofthe ody is proportional othto the magnitude of the force
and to the moment arm d,which is the perpendicular
distance from the a"is to theline of action of the force
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The Right +and Rule
The moment is a ector Mperpedicular to the plane of theody' The sense of M dependson the direction in which F
tends rotate the ody' Theright hand rule, Fig' -'.'c, isused to identify this sense'
/e represent the moment of Faout *&* as a ector pointingin the direction of the thum,with the ngers curled in thedirection of the rotationtendency
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/hen dealing with forceswhich all act in a gien plane,we customarily speak of themoment aout a point
By this we mean the momentwith respect to an a"is normalto the plane and passingthrough the point
The moment of force F aoutpoint 0 in Fig' -'.'d' has themagnitude M 1 F'd and iscounterclockwise
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2*3 B45## 6*7
*M #+0%T$ #+0%T$ #+0%T$ *M7
/0##040M 040$8M /0R*+M0T440+$ /0B0R*80T+7
%0M0#T5
THANK
YOU