When a compression wave travel through a median, which way does matter in the median move?

(D) 42.4N

Explanation:

Since the frame is at rest, the net force acting on it must be 0. There are three forces acting on it: the gravity and the opposing forces of the two cables.

Since the gravity is a vertical force, we are only interested in the vertical components of the remaining forces. The net force equation is

F_net = 0 = F_g -2 * F_y

The vertical force of one cable (using the information in the drawing) is:

F_y = 30N * sin 45 deg = 21.21N

Now the weight can be determined:

0 = F_g - 2 * F_y

F_g= 2 * F_y = 2 * 21.21N = 42.4N

The weight of the frame is about 42.4N.