The Following procedure is recommended when dealing with problems involving the application of Newton’s laws:
Draw a simple, neat diagram of the system.
Isolate the object whose motion is being analyzed. Draw a free-body diagram of this object, that is, a diagram showing all external forces acting on the object. For systems containing more than one object, draw separate free body diagram for each object. Do not include in the free-body diagram forces that the object exerts on its surroundings.
Establish convenient coordinate axes for each object and find the components of the forces along these axes. Apply Newton’s second law, ΣF = ma, in component form. Check your dimensions to make sure that all terms have units of force.