Question

A photo frame with a mass of 2.8 kg is hung from a nail according to the opposite figure. If we know that the nail is located exactly in the middle of the string and the frame does not touch the wall, how many newton is the tensile strength of the string?

Answer 1

One string (side of) must support 1.4 kg.

T cos 15 = vertical force required by each side of the string

T cos15 = 1.4 * 9.8 N

T = 1.4 * 9.8 / cos 15 = 14.2 N