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Cosine and Sine rules to get magnitude and direction of a resultant force

  • Thread starter baylayA
  • Start date
  • #1
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Use the cosine and sine rules to determine the magnitude and direction of the resultant of a force of 11 kN acting at an angle of 50 degrees to the horizontal and a force of 6 kN acting at an angle of -30 degrees to the horizontal.

helppp please
 

Answers and Replies

  • #2
danago
Gold Member
1,122
4
What have you tried doing? Have you drawn a diagram of the situation -- Will make things much easier.
 
  • #3
14
0
No i haven't.
Do you know how to find resultant forces with forces and angles from axises? because I have another problem like that and i have no idea how to do them
 
  • #4
danago
Gold Member
1,122
4
Well maybe draw one then :smile: At least then you actually have a triangle to apply the cosine and sine rules to.

If you are given forces and angles relative to axes, you could again do the same thing and form a triangle to be solved with geometry, or perhaps easier would be to resolve each force into a horizontal and vertical component and add the components.
 
  • #5
2
0
Hi All
to get magnitude of resultant use cosin rule R^2= X^2+Y^2 – 2XYcosβ
to get the direction use sine rule = (Sin β /length of opposite line) = (sinθ/ length of opposite line)
 

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