Coordinate System. Since the angular motion of the arm is
reported, polar coordinates are chosen for the solution, Fig. 12—32a.
Here f) is not related to r, since the radius is constant for all f).
Velocity and Acceleration. It is first necessary to specify the first
and second time derivatives of r and f). Since r is constant, we have
Thus,
The amusement park ride shown in Fig. 12—32a consists of a chair that
is rotating in a horizontal circular path of radius r such that the arm 0B
has an angular velocity i) and angular acceleration 0. Determine the
radial and transverse components of velocity and acceleration of the
passenger. Neglect his size in the calculation.
— rå2
n
—a, = rö2
(b)
(a)
SOLUTION
Fig. 12-32
ar = — rå2
+ 2hå ro
*Ihese results are shown in Fig. 12—32b
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