Motion in a Plane - Result Question 60
63. An electric fan has blades of length $30 cm$ measured from the axis of rotation. If the fan is rotating at $120 rpm$, the acceleration of a point on the tip of the blade is
(a) $1600 ms^{-2}$
(b) $47.4 ms^{-2}$
(c) $23.7 ms^{-2}$
(d) $50.55 ms^{-2}$
[1990]
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Solution:
- (c) Centripetal acc. $=\omega^{2} r=4 \pi^{2} v^{2} r$
$ \begin{matrix} =4 \times(3.14)^{2} \times \frac{120}{60} \times \frac{30}{100}=23.7 ms^{-2} \\ {[\because \omega=2 \pi \nu]} \end{matrix} $
