Conceptual Dynamics - Independent Learning

General Planar Motion - Example Problem 4.3-4


Consider the following diagram of a piston assembly in an internal combustion engine. The crankshaft OA is rotating at a constant rate of 2000 rpm counter-clockwise. If the piston is at top dead center position (θ = 0o), determine ...


  1. the velocity of the piston head B,
  2. the angular velocity of the connecting rod AB, and
  3. the angular acceleration of the connecting rod AB.




  • ωOA = 2000 rpm ccw = constant
  • θ = 0o
  • lOA = 0.1 m
  • lAB = 0.2 m



  1. vB
  2. ωAB
  3. αAB


Familiarize yourself with the system.
  • Note fixed point O.
  • Assign the directions of the angular velocities and angular accelerations.
  • Note that piston B is constrained to move only up and down.


Click on the figure after you have familiarized yourself with the system and drawn a schematic illustration.


Analyze the motion of link OA. Find the velocity of joint A. Which equation should be used?