Question

3.

Answer 1

Answer:

120°

Explanation:

Draw a free body diagram.  There are three forces acting on the traffic light.  Two tension forces acting along the cables, and weight.

The tension forces have an angle θ between them.  That means each tension force forms an angle of θ/2 with respect to the vertical.  So the y component of each tension force is:

Ty = T cos (θ/2)

Sum of the forces in the y direction:

∑F = ma

Ty + Ty − W = 0

2 Ty = W

Substituting:

2 T cos (θ/2) = W

If W = T, then:

2 W cos (θ/2) = W

2 cos (θ/2) = 1

cos (θ/2) = 1/2

θ/2 = 60°

θ = 120°