Can you tell from an FBD if an object is moving or not? Explain your response.

Yes it is possible to tell if an object is moving or not using a FBD based on Newton's Laws of Motion

Explanation:

A Free Body Diagram is the representation of an object in a diagram that shows (all) the vector of the forces that act on the object

When the sum of all the force vectors acting on the body give a resultant force the object will move in the direction of the force according to Newton's First Law of motion, which states that an object will continue in its rest state or   continue its uniform motion on a straight path unless a force acts on the object

The net force, 'F', can be represented according to Newton's Second Law of motion which is F = m·a, where 'a' represents the acceleration (rate of change in velocity) of the object as the object begins to move from rest

Therefore;

From a FBD it is possible to tell if an object is moving or not.

a coal burning power plant

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.