Question 688: Centre of Mass and Rotational Motion

Question

A wheel having moment of inertia 2 kg m2 about its vertical axis, rotates at the rate of 60 rpm about this axis. The torque which can stop the wheel's rotation in one minute would  be

Accepted Answer

$${\omega _f} = {\omega _i} - \alpha t \Rightarrow 0 = {\omega _i} - \alpha t$$
$$ 	herefore $$ $$\alpha  = {{{\omega _i}} \over t}$$ where $$\alpha $$ is retardation.
The torque on the wheel is given by
$$	au  = I\alpha  = {{I\omega } \over t} = {{I.2\pi \upsilon } \over t} = {{2 	imes 2 	imes \pi  	imes 60} \over {60 	imes 60}}$$
$$	au  = {\pi  \over {15}}$$ N m
This is the torque required to stop the wheel in
1 min. (or 60 sec.).

Answer

$${{2\pi } \over {15}}$$ N m

Answer

$${\pi  \over {12}}$$ N m

Answer

$${\pi  \over {15}}$$ N m

Answer

$${\pi  \over {18}}$$ N m

Centre of Mass and Rotational Motion

A wheel having moment of inertia 2 kg m2 about its vertical axis, rotates at the rate of 60 rpm about this axis. The torque which can stop the wheel's rotation in one minute would be

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