Practice: Inclined Plane Theory

Inclined Plane

  • Sliding down an inclined plane is another example of motion with constant acceleration.
  • Source of the motion is still gravity of earth but only part of it is affecting the sliding of the object
  • To find the acceleration of an object over an inclined surface, one should first find the acceleration using the second law of Newton
  • For inclined surfaces, it is easier to choose the coordinates such that x-axis is parallel to the surface and y-axis is perpendicular to the surface.
  • Find the acceleration in the x and y direction shown in the free body diagram below.


Free body diagram of a skier of mass m glides down a slope at angle θ. We assume the snow is frictionless.










  • Note that usually the sliding object always remains in contact with surface which means that there is no motion along the y-axis we defined above!

More Free Body Diagrams Questions:
More Inclined Surfaces Questions: