Today’s Objectives:Students will be able to: 1.Describe the velocity of a rigid body in terms of translation and rotation components.2.Perform a relative-motion velocity analysis of a point on the body. RELATIVE MOTION ANALYSIS: VELOCITYIn-Class Activities:•Check Homework•Reading Quiz•Applications•Translation and Rotation Components of Velocity•Relative Velocity Analysis•Concept Quiz•Group Problem Solving•Attention Quiz
READING QUIZ1.When a relative-motion analysis involving two sets of coordinate axes is used, the x’ - y’ coordinate system willA)be attached to the selected point for analysis.B)rotate with the body.C)not be allowed to translate with respect to the fixed frame.D)None of the above.2.In the relative velocity equation, vB/Ais.
APPLICATIONSAs the slider block A moves horizontally to the left with vA, it causes the link CB to rotate counterclockwise. Thus vBis directed tangent to its circular path. Which link is undergoing general plane motion? Link AB or link BC?How can the angular velocity, ϖof link AB be found?
APPLICATIONS (continued)Planetary gear systems are used in many automobile automatic transmissions. By locking or releasing different gears, this system can operate the car at different speeds.How can we relate the angular velocities of the various gears in the system?