Determine the unstretched length of spring AC

Determine the unstretched length of spring AC if a
force P = 80 lb causes the angle u = 60° for equilibrium.

[HowTomin-coni]

I love it when he says please comment below if you want me to do any problem and I will be happy to help.

[GilmooreZ]

@4:06 at the Σy, it should be F(AB)sin(60), not cos(60) to get the 0.866F(AB). The process of elimination was properly executed simply because the angles used are the angles in special right triangle (30-60-90). Nevertheless, you could get its real values on the proper algebraic process.

[russellnasrallah]

@4:16 when you multiply by (0.866/0.5), I don't particularly understand why you made that choice as opposed to bringing the -0.5Fab to the right side of the equation and then solving for either of the unknowns in terms of the other, then plugging into equation (1).

[markallenfrancisco]

What if the angle theta is unknown ..how to find it??

[ranaasif]

Plz can you explain same problem but they never gave angle θ

[xamos]

(l - lc) it looks like * I had 2 minutes until due time m. 😭

[merryfrank]

please work on you voice, its quite inaudible, makes the class a bore and impends understanding