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Acceleration. Taking the time derivative of the velocity equation
yields a similar relationship between the instantaneous accelerations
of A and B
2
d AB
a B = a A + dt 2 . 2-45

46 Planar Rigid Body Motion

In this chapter, the planar kinematics of a rigid body will be
discussed. This study is important for the design of gears, cams, and
mechanisms used for many mechanical operations. Once the
kinematics is thoroughly understood, then we can apply the equations
of motion, which relate the forces on the body to the bodies motion.

a b

c d
Fig. 2-16.

The planar motion of a body occurs when all the particles of a
rigid body move along paths which are equidistant from a fixed plane.
There are three types of rigid body planar motion, in order of
increasing complexity, they are

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