Finding the resultant force using a vector polygon diagram

Bolter · Sep 28, 2020

Hi I made an attempt at this problem but have got the wrong answer

Diagram of three forces acting at a point on x and y axes: F1 = 5 N along the positive x-axis, F2 = 10 N at 30° above the x-axis, F3 = 20 N at 45° left of the y-axis.

Printed problem part (c): if F2 and F3 act in the opposite direction, determine the FR resultant force (vector and direction) on the ring, and draw the vector polygon for the forces in Figure 1.2 to verify it, then find the equilibrant force.

Handwritten notes on lined paper showing a vector system with forces F1, F2 and F3 at angles on x-y axes, a polygon method diagram, sums of x and y components, a resultant force of 19.91 N and an equilibrant explanation.

The correct answer is actually resultant force = 21.767 N at 61.34 degrees (or 151.34 degrees bearing), but I don't know how they got that?

Any help would be appreciated! Thanks

Lnewqban · Sep 28, 2020

Are you including F1?

Bolter · Sep 28, 2020

Lnewqban said:

Are you including F1?

Oops, I initially thought the Q wanted me to solely focus on force F2 and F3 and ignore F1. I think I got the answer now when taking F1 into account

I got resultant force to be 21.82N at angle 61.30 degrees, which is slightly different from the correct answer given. But I thinks it's because of rounded values.

Finding the resultant force using a vector polygon diagram

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