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Moment's question

Determine the moment of the 60N force about point A on the perimeter of the disk by determining the lever arm of the force:
(Note, the lever arm is the perpendicular distance from the line of action of the force to the point where the moment is to be taken about)

(edited 11 years ago)
Reply 1
Any ideas?

I cannot calculate the perpendicular distance from the line of action of the force to the point A.
I have tried calculating the lengths of the other lines that would add up using pythagoras theorem to obtain the perpendicular, but I can't find the necessary angles.
(edited 11 years ago)
Reply 2
Original post by sulexk
Any ideas?

I cannot calculate the perpendicular distance from the line of action of the force to the point A.
I have tried calculating the lengths of the other lines that would add up using pythagoras theorem to obtain the perpendicular, but I can't find the necessary angles.


Calculate AC by the cosine rule. The angle AOC is 165. AO=OC=250
The angle between AC and the force is 60 (75-15).
The perpendicular distance (d) d=AC*sin 60
moment.png
(edited 11 years ago)
Reply 3
Original post by ztibor
Calculate AC by the cosine rule. The angle AOC is 165. AO=OC=250
The angle between AC and the force is 60 (75-15).
The perpendicular distance (d) d=AC*sin 60
moment.png


Thank you very much :smile:

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