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Resultant force from three forces.

  • Thread starter Colts
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  • #1
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Homework Statement


http://session.masteringengineering.com/problemAsset/1127110/6/Probs.2-39_40.jpg
I will refer to this picture for the problem.
I have to find the resultant of the three force vectors. I know all except F1 and theta. I am given it for this problem to find the resultant. F1=510N and theta=20 degrees.


Homework Equations


Each theta is the degrees from positive x axis.
Fx1cos(theta1)+Fx2cos(theta2)+Fx3cos(theta3)=x
Fy1sin(theta1)+Fy2sin(theta2)+Fy3sin(theta3)=y
sqrt(x^2+y^2)=answer


The Attempt at a Solution


510cos(70)+600cos(150)+400cos(30)=1.22
510sin(70)+600sin(150)+400sin(30)=979.24
sqrt(1.22^2+979.24^2)=979.24
 

Answers and Replies

  • #2
Redbelly98
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Welcome to Physics Forums.

For the 600 N force, the angle is not 150°. Look carefully at the figure again.
 
  • #3
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The angle for 600N should be 4/5 for the x direction and 3/5 for the y direction. Now how do I find the angle? Thats the next part.

Edit: Nevermind. I got it. Thank you
 

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