A fan is rotating with an angular speed $300 \mathrm{rpm}$. The fan is switched off, and it takes $80 \mathrm{~s}$ to come to rest. Assuming constant angular deceleration, the number of revolutions made by the fan before it comes to rest is

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Aicharya · Accepted Answer

As $\omega=\omega_0+\alpha \mathrm{t}$ $ \begin{aligned} & \Rightarrow \mathrm{f}=\mathrm{f}_0+\frac{\alpha}{2 \pi} \mathrm{t} \ & \Rightarrow 0=5+\frac{\alpha}{2 \pi} 	imes 80 \ & \Rightarrow \alpha=-\frac{10 \pi}{80}=-\frac{\pi}{8} \mathrm{rad} / \mathrm{sec}^2 \end{aligned} $ So, $	heta=\frac{1}{2} 	imes \frac{\pi}{8} 	imes 80^2$ $ =400 \pi $ No. of revolution $=\frac{400 \pi}{2 \pi}=200$

A fan is rotating with an angular speed $300 \mathrm{rpm}$. The fan is switched off, and it takes $80…

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