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where
v 2
v
a = ɺ and a = ρ 2-35
n
t
The tangential component of acceleration represents the time
rate of change in the magnitude of the velocity. The normal
component of acceleration represents the time rate of change in the
direction of the velocity. Since a always acts towards the center of
n
curvature, this component is sometimes referred to as the centripetal
(or center seeking) acceleration. The binormal component of
acceleration always equals zero a b ≡ 0
These two mutually perpendicular components are shown in Fig.
2-13,d. Therefore, the magnitude of acceleration is the positive value
of
2
2
a= a + a 2-36
n
t
Fig. 2-14.
As a result of these interpretations, a particle moving along the
curved path in Fig. 2-14 will have accelerations directed as shown.
44 Classification of Motion of a Particle by its Acceleration
Classifying motion of particle is possible variously. For
example, by a trajectory distinguish a rectilinear and curvilinear
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