Hello!
I suppose we apply a constant braking force perpendicularly to the radius of spin. Then the torque
(moment of force) will be
From the other hand, this torque will cause an angular acceleration (deceleration in this case) and the relation between them is
where
is the moment of inertia of a centrifuge.
For an object whose mass is at the constant distance from the axis of rotation,...
Hello!
I suppose we apply a constant braking force perpendicularly to the radius of spin. Then the torque
(moment of force) will be
From the other hand, this torque will cause an angular acceleration (deceleration in this case) and the relation between them is
where
is the moment of inertia of a centrifuge.
For an object whose mass is at the constant distance from the axis of rotation, the moment of inertia is Linking this together, obtain
or
The angular speed will decrease uniformly at a rate
A centrifuge stops when
so
where
is the initial angular speed and
is the given time of braking.
Finally, all these quantities are given. The only problem is that
is given in rpm, while it is required in radians per second. One rpm is
radians per second, so the final answer is
This is the braking force. The torque itself is
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