ENGR 230 Dynamics Sections 16'1 16'3

1
ENGR 230 Dynamics Sections 16.1 16.3
2
Rigid Body Motion

• When all the particles of a rigid body move along
  paths which are equidistant from a fixed plane
  the body is said to undergo planar motion.

• Three types of planar motion
• Translation
• Rectilinear
• Curvilinear
• Rotation about a fixed axis
• General Plane Motion

3
Rigid Body Planar Motion
4
Rigid Body Motion Example
5
Translation
6
Rotation about a Fixed Axis

• Angular Motion
• Angular Position
• Angular Velocity
• Angular Acceleration

7
Rotation about a Fixed Axis
8
Rotation about a Fixed Axis with Constant Angular
Acceleration
9
Motion of a Point P

• Position
• Velocity

10
Motion of a Point P

• Acceleration

11
Motion of a Point P

• Acceleration

12
Motion of a Point P
13
Lecture Example You have been asked to help
design a Human Powered Paper Vehicle for some of
your classmates. They designed their vehicle
with 4815 gears, where the first number is the
front sprocket and the second number is the rear
sprocket. If their vehicle has 16 inch wheels
and their maximum pedal cadence is 80 rev/min, is
their gearing adequate to complete the 300m (900
ft) course in under 2 minutes with 2 rider
changes at 15 seconds each.
14
Lecture Example Determine the angular velocity
and acceleration after the mass-less 0.5 m radius
disk has rotated 10 times starting from rest.
15
Lecture Example The angular velocity of the
disk is defined by ?(5t22) rad/sec. Determine
the magnitude of the velocity and acceleration
when t0.5 seconds of Point A.