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

2. Chapter 18 Planar Kinetics of Rigid Bodies: Work and Energy

3. Kinetic Energy

4. General
Translation
Rotation

5. Rotation

6. General Plane Motion (Translation and Rotation)

7. 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

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

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

10. The work of a force

11. Work of a Spring Force

12. 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

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

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

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

16. Thank you