Plane Kinematics of Rigid Bodies Instantaneous Center of

Plane Kinematics of Rigid Bodies - Instantaneous Center of Zero Velocity Method Lesson 14 Section 5/5 • So far we have discussed the Absolute Motion method and the Relative Motion method to solve for the velocities of points on rigid bodies. • Let’s start with an example problem where we use the Relative Motion method. © D. J. Morrison, 2013 1

Example Problem: L 14 -1 © D. J. Morrison, 2013 2 Meriam and Kraige, 6 th, Wiley

Example Problem: L 14 -1 Meriam and Kraige, 6 th, Wiley Given: FAS, v. A = 2 m/s , = 30 Find: © D. J. Morrison, 2013 AB and v. G 3

• Instantaneous Center of Zero Velocity – For plane motion, at any instant, the motion may be considered as pure rotation about a point called the instantaneous center of zero velocity (IC) • Only valid for the instant considered. • Only works for velocity – not acceleration !!!! • IC moves as the body moves and does not maintain the same relationship to points on the rigid body. – Works well if we know the directions of the velocity vectors of two points on the rigid body. © D. J. Morrison, 2013 4

IC Method Steps: 1. Identify directions of velocity vectors of two points. 2. At these two points draw lines perpendicular to the velocity vectors. 3. These lines intersect at the IC point C. Fig 5/7 Meriam and Kraige 4. If we know the magnitude of v. A or v. B you can solve for . © D. J. Morrison, 2013 5

Example Problem: L 14 -2 © D. J. Morrison, 2013 6