A flat uniform circular disk has a mass of 3.10 kg and a radius of 76.0 cm. It is suspended in a horizontal plane by a vertical wire attached to its center. If the disk is rotated 1.50 rad about the wire, a torque of 0.0750 N·m is required to maintain the disk in this position.
Alright, so I understand that Torque=-k(theta)
And I realize that using the equation T=2pi sqrt(I/k), I can easily rearrange it to solve for my rotational inertia. However, I don't know what the time period is, which leads me to use my mass and my radius. There are no equations in my notes/books and I can't think of where to apply these two knowns. So, how can I use these to find my Time Period (T)?
Alright, so I understand that Torque=-k(theta)
And I realize that using the equation T=2pi sqrt(I/k), I can easily rearrange it to solve for my rotational inertia. However, I don't know what the time period is, which leads me to use my mass and my radius. There are no equations in my notes/books and I can't think of where to apply these two knowns. So, how can I use these to find my Time Period (T)?
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Moment of inertia of a disc is 1/2 . M . R^2 = 0.5 . 3.1 . 0.76^2 = 0.895 kgm^2
You have worked out "k" , so just plug em in for T
You have worked out "k" , so just plug em in for T