Energy Conservation
In solving physics problems involving energy conservation, it is important to recognize how kinetic and potential energy change. Despite these individual changes, if no non-conservative forces act on the subject, the sum of kinetic and potential energy (i.e., the mechanical energy) remains constant. However, if work is done on the subject by non-conservative forces, the mechanical energy decreases or increases, depending on whether the work done by the non-conservative forces is positive or negative.
For each of the following problems, build an energy bar chart showing the relationships among the forms of energy at two different points in time. For these particular problems you need to show only qualitative relationships. Note carefully the statement of the origin of the coordinate system, since that will affect the result.