Forces in Two Dimensions - Mission F2D4 Detailed Help

A sign that weighs 100 N is supported symmetrically by two cables that make an angle of 20.0 degrees with the horizontal. A single cable will pull upward on the sign with a force of ____ Newtons. 

(Note: Numbers are randomized numbers and likely different from the numbers listed here.)

Definition of Equilibrium:
is the condition in which all the individual forces acting upon an object are balanced.

If a sign is at equilibrium, then the individual forces acting upon the sign are balanced. Thus, there is no unbalanced force - the net force is 0 Newton. In order for the net force to be 0 N, there must be a balance of both horizontal and vertical forces. If the sign is supported by two cables, each cable must pull with sufficient enough upward force to balance the weight of the sign (the downward force of gravity). Thus, if the sign weighs 100 N, the upward components of tension in each cable must together provide 100 N of upward force.