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Grade 11Mechanics

the moment of inertia of a fly wheelmaking 300 revolutions per minute is 0.3kgm².find torque required to bring it to rest in 20 sec?

zeeshan siddiqui

10 Years agoGrade 11

1 Answer

arun

Approved Tutor Answer10 Years ago

it is given that the angular velocity of fly wheel is 300 rpm = $10\pi$ rad/s

and t= 20 sec

let initial angular velocity be $\omega$ and final be $\varpi$

so, $\omega = 10\pi$ , $\varpi = 0$

let angular acceleration is $-\alpha$

using first equation of rotational motion,

$\varpi = \omega - \alpha t$

$10\pi = 20\alpha$

$\alpha=\frac{\pi}{2}$

and $\tau =I\alpha \Rightarrow \tau = 0.3\times \frac{\pi}{2}$

$\tau =0.15\times 3.14 \Rightarrow \tau= 0.47$ Nm

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