Force?

It's given already.

Sum of forces up and down is zero. Sum of forces right and left is zero. Sum of couple forces is zero. You take it from there.

and a little geometry, i should say, if your concern is the axial forces on the links for your design.

HOMEWORK ALERT!

if this is a roof structure in Buffalo you might have issues

If there were Buffalo's cops in snowshoes standing on it there would be the police force to contend with as well. Perhaps it would easier just to convert this picture to its thousand-word equivalent and measure the combined force resulting from the black pixels.

It might be a Polygone bike!

The picture itself is just an image on my laptop. The force on this image is a meaningless attribute.

The diagram in the picture is not clear enough for me to say anything but that it looks like a homework assignment about a truss design. As the CR4 FAQ states, we do not do others homework. This is a disservice to the student. I will say that it looks like whomever wrote this imaged document already performed a lot of the work on the multiple forces involved in this truss. If you ask an intelligent question about a part of this work you will likely get some help here. Asking for an unspecified force to be calculated implies little comprehension of the topic.

herehttp://www.wendrickstruss.com/calculator/

If you're near sea level, it would be about 15 pounds per square inch multiplied by the surface area of the picture in square inches.

You can also consider the force of the table pushing back on the picture, which is equal to the picture's weight, but that's probably negligible.

Force = mass x acceleration

The acceleration due to gravity is 9.81 m/s2, but we don't know the mass of the picture. Therefore, for us to assist with your homework, please advise the mass of the picture.