Imagine that you are given a description of a real-life situation and are asked to analyze the motion of the objects involved.

Imagine that you are given a description of a real-life situation and are asked to analyze the motion of the objects involved. Frequently, that analysis involves finding the acceleration of the objects, which, in turn, requires that you find the net force.To find the net force, you must first identify all of the forces acting on the object and then add them as vectors. Such a procedure is not always trivial. It is helpful to replace the sketch of the situation by a drawing of the object (represented as a particle) and all the forces applied to it. Such a drawing is called a free-body diagram. This problem will walk you through several examples of free-body diagrams and will demonstrate some of the possible pitfalls.Here is the general strategy for drawing free-body diagrams:Identify the object of interest. This may not always be easy: A sketch of the situation may contain many objects, each of which has a different set of forces acting on it. Including forces acting on different objects in the same diagram will lead to confusion and a wrong solution.Draw the object as a dot. Draw and clearly label all the forces acting on the object of interest. The forces should be shown as vectors originating from the dot representing the object of interest. There are two possible difficulties here: omitting some forces and drawing the forces that either don't exist at all or are applied to other objects. To avoid these two pitfalls, remember that every force must be applied to the object of interest by some other object.Once all of the forces are drawn, draw the coordinate system. The origin should coincide with the dot representing the object of interest and the axes should be chosen so that the subsequent calculations of vector components of the forces will be relatively simple. That is, as many forces as possible must be either parallel or perpendicular to one of the axes.Consider a block pulled by a horizontal rope along a horizontal surface at a constant velocity as shown. (Part B figure) There is tension in the rope. Which of the following forces act on the block? Check all that apply.