Graphs for an Object in Mechanical Equilibrium
Towards the bottom right-hand corner of the simulation page, click on the drop-down arrow under "Choose an Object." Then, in the drop-down menu, select "Refrigerator." See the images below. Click on the images to enlarge.
On the left-hand side of the simulation window, de-select the F with "Applied" subscript. See the image below and at the left. Click the image to enlarge.
Then, select the F with "Sum" subscript. See the image below. This selection insures that the graph we generate is the Net Force Versus Time Graph, which is what we want.