Lecture 5: Angular Kinetics

1
Lecture 5 Angular Kinetics
2
Eccentric Force

• force that does not pass through the axis of
  rotation
• causes angular motion

3
Force vs. Motion

• concentric force linear motion only
• couple angular motion only
• eccentric force general motion (linear angular)

4
Center of Gravity (CG)

• the perfect balance point
• center of mass (CM)
• inside or outside of the object

5
(No Transcript)
6
(No Transcript)
7
Reaction Board Method
8
Segmental Method
9

• BSPs
• masses of the segments
• CM locations of the segments

10
Moment of Inertia

• inertia of object in angular motion
• single particle
• rigid body
• unit kgm2

11
(No Transcript)
12
(No Transcript)
13

• pendulum method
• Parallel-axis theorem

14
Moment of Force (Torque)

• turning effect produced by a force

• cause of angular motion
• unit Nm

15
Moment Arm

• perpendicular distance from the axis of rotation
  to the line of action

• changes as the angle changes

16
(No Transcript)
17
(No Transcript)
18
Resultant Moment
Fig 6-6
19
Newtons Laws of A. M.

• law of angular inertia
• If T 0, w const.
• law of angular acceleration
• law of angular reaction

20
Equilibrium
Fig 6-7
21
Levers

• elements

• equilibrium

22

• mechanical advantage (gain)
• G gt 1 advantage in force
• G lt 1 disadvantage in force

23
br
FA
bb
b
24

• classes

25
(No Transcript)
26
(No Transcript)
27
Stability and Equilibrium

• types
• stable equilibrium
• unstable equilibrium
• neutral equilibrium
• factors
• base of support
• weight
• Height of CG

28
(No Transcript)
29
Angular Momentum

• amount of angular motion
• unit kgm2/s

30

• remote local terms

31

• a. m. conservation
• if T 0, H const.

32

• Transfer of a. m.
• overall H remains constant
• H of each body part may change

33
Centripetal Acceleration

• radial acceleration
• centripetal force
• centripetal vs. centrifugal