Component method vector problem

AI Thread Summary
The discussion focuses on using the component method to determine the resultant force's direction and magnitude from three given forces. The calculations for the components Ax, Ay, Bx, By, Cx, and Cy were presented, leading to a resultant vector R with a magnitude of 527N. A participant pointed out a potential typo in the tangent calculations, clarifying that the correct values should be 181.6 and 495.1. Additionally, it was emphasized that the angle should be specified in relation to the coordinate axes for clarity. Overall, the calculations were mostly correct, with minor adjustments needed for precision.
ur5pointos2sl
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Use the component method to find the resultant(direction and magnitude) of the three forces shown.

Could someone please verify my answers or tell me where I went wrong.

Ax = 500 Cos 30 = -433N
Ay = 500 Sin 30 = -250N
Bx=-250 N
By= 0
Cx=200 Cos 20 = 187.9N
Cy= 200 Sin 20 = 68.4N

R = (-433-250+187.9)I + (-250 + 0 + 68.4)j
= (-495.1, -181.6)
R = sqrt(-495.1^2 + -181.6^2)
= 527N

Tan Theta = 318.4 / 370.9
Theta = 20.1 deg.
 

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ur5pointos2sl said:
Use the component method to find the resultant(direction and magnitude) of the three forces shown.

Could someone please verify my answers or tell me where I went wrong.

Ax = 500 Cos 30 = -433N
Ay = 500 Sin 30 = -250N
Bx=-250 N
By= 0
Cx=200 Cos 20 = 187.9N
Cy= 200 Sin 20 = 68.4N

R = (-433-250+187.9)I + (-250 + 0 + 68.4)j
= (-495.1, -181.6)
R = sqrt(-495.1^2 + -181.6^2)
= 527N
That seems right.

Tan Theta = 318.4 / 370.9
Theta = 20.1 deg.
Looks like the "318" and "370" are typos, and that you actually (and correctly) used 181.6/495.1 instead.

You'll also need to specify which half-axis that angle is measured from (+x, +y, -x, or -y), and whether the angle is above/below/right/left of that half-axis.

If you don't specify that, people normally assume it's from the +x axis, in the counterclockwise direction.
 
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