Question

a street lamp weight 150n. It is supposed by two wires that form an angle of 120 with each other. the tensions in the wires are equal
a) what is the tension in each wire supporting the street lamp?
b) if the angle between the wires supporting the street lamp is reduced to 90, what is the tension in each wire?

Answer 1

Draw a free body diagram as so, then apply your forces.
Use summation of "x" and "y" components of force then set it equal to zero. After you have done that and found the forces of T1(x), T1(y), T2(x), T2(y), use the Pythagorean theorem to find the Tension of the string. Since they are at the same angles, they should be equal to other.

In other words they are splitting the work of keep up the 150 N street lamp