The acceleration vector a
is at each instant of time t given by
the time derivative of the velocity vector
v.
  
| 
a(t) =
dv(t)/dt =
 | 
(
 | 
 | 
)
 | 
=
 | 
(
 | 
| 
-ω2R cos(ωt)
 | 
 
| 
-ω2R sin(ωt)
 | 
 
 
 | 
)
 | 
 
 
 
since
 
dvx(t)/dt
= d( -ωR sin(ωt) )/dt
= -ω2R cos(ωt)
 
and
 
dvy(t)/dt
= d( ωR cos(ωt) )/dt
= -ω2R sin(ωt)
 
The resulting acceleration vector is indicated in the above video.
Notice that a and v
are perpendicular and, consequently,
that a and r
are parallel.
 
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