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?

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

& Explanation:

small scaled building models are very rare to make/build nowadays.

due to advance technology it is more wiser and more convenient to use 3d programs like revit in creating building model to scale.

so It is always a good idea to make models of your ideas, before deciding on the final design.

This will help you determine whether your idea is going to work or needs modifying. A model allows you to test your solution quickly and cheaply.

Reworking a massive building takes years, millions of pounds, and meticulous planning and project management.