King Fahd University of Petroleum & Minerals Mechanical Engineering Dynamics ME 201 BY Dr. Meyassar N. Al-Haddad Lecture # 36

Chapter 18 Planar Kinetics of Rigid Bodies: Work and Energy

Kinetic Energy

General Translation Rotation

Rotation

General Plane Motion (Translation and Rotation)

Example Total K.E. ? K.E. of the Body of Bike and man ( translational ) K.E of the wheel ( Translational + Rotational ) Total K.E. = 2 Twheel +T B+Man

mB=6 kg mD=10 kg mC=12 kg No slipping Total K.E = ? Example 18-1 Block (Translation) Disk (Rotation) Cylinder ( Translation &Rotation)

Problem wAB=wCD=10 Ib wBC=20 Ib Total K.E = ?

The work of a force

Work of a Spring Force

Force That Do No Work Force Perpendicular to the displacement Weight Normal reaction Rolling resistance force Fr Fr acts at point which has zero velocity The point is not displaced

Pin Reaction Ox Oy On Ot Pin Reaction Do No work Act on zero velocity and create no displacement

The Work of a couple -Do work only when the body undergoes a rotation -Translation : positive work cancels the negative work -Rotation

Example 18-2 m =10 kg M = 50 Nm P = 80N, unstretched 0.5 m total work ?

Thank you