How do you determine the components Fa and Fb of a 3.1 kN force along the oblique axes a and b.?

[790]

Determine the components Fa and Fb of the 3.1 kN force along the oblique axes a and b.

F is 30 degrees up from the x axis, a is 17 degrees up the x axis, and b is 16 degrees down from the y axis.

How do you do this problem?

[Bramble]

I assume F is the 3.1 kN force.

The angle between F and a is (30-17) = 13° so the component of F in the direction of a is:
Fa = F.cos(13°) = 3.1×0.97437 = 3.0205 kN.

The determination of Fb is not so easy, only because it's unclear what "down" from the y-axis means. Let's assume it puts Fb 16° into the second quadrant; then the component of F in the direction of b is:
Fb = F.cos(106 – 30) = 3.1×cos(76°) = 0.75 kN.