The inclined plane is a useful system to really show the power of Newton’s Second Law. It is also one of the first situations in which we specifically alter the coordinate system to simplify the analysis. Rotating the coordinate system makes a two-dimensional situation into a one dimensional problem.
You are using an incline when you go up or down accessibility ramps, a sliding boards, or when you ride the tracks up and down the hillsides in Pittsburgh, PA, Johnstown, PA, or Niagara Falls, ON.
The normal force, frictional force, and net acceleration all change when objects move on these planes. If you are careful with geometry, you can find useful information by applying Newton’s Second Law appropriately.
The sections below go into the the specifics.
Topics under Inclined Plane
Be careful later in the semester when you look at banked curves. The free body diagrams look similar, but in those situations, you should not rotate the coordinate system.