A traffic light of weight 100 N is supported by two ropes as shown in Fig. on the right. What are the tensions in the ropes? A) 50 N
B) 63 N
C) 66 N
D) 83 N

83 N

Explanation:

Draw a free body diagram of the traffic light.  There are three forces:

Weight force 100 N pulling down,

and tension forces T pulling along the ropes.

Sum of forces in the y direction:

∑F = ma

2 (T sin 37°) − 100 = 0

T = 83 N

two charges are fixed in place on the x-axis as shown. the charge at x = 0 is negative and has magnitude q = 2 μcoulombs (1 μcoulomb = 10-6 coulombs). the charge at x = d, (d = +12 cm), is positive and has magnitude q = 4 μcoulombs. find a point x = xo along the x-axis at which the electric field is zero.

electrical power