A torsional pendulum consists of a disk of mass 450 g and radius 3.5 cm, hanging from a wire. If the disk is rotated through an angle of 45o and released from rest and oscillates with a frequency of 2.5 Hz, what is maximum angular speed of the disk?

Respuesta :

Answer:12.34 rad/s

Explanation:

We know in torsional pendulum

[tex]I\ddot{\theta }=-k\theta [/tex]

[tex]\ddot{\theta }+\omega ^2\theta =0[/tex]

[tex]\omega ^2=\frac{k}{I}[/tex]

general equation of it

[tex]\theta \left ( t\right )=\theta _0cos\omega t[/tex]

and at t=0  \theta =45[/tex]

[tex]\frac{\pi }{4}=\theta _0[/tex]

[tex]\theta \left ( t\right )=\frac{\pi }{4}cos\omega t[/tex]

and [tex]\omega =2\pi f=5\pi [/tex]

For angular velocity

[tex]\frac{\mathrm{d}\theta }{\mathrm{d}t}=-\frac{5\pi ^2}{4}sin5\pi t[/tex]

Maximum angular velocity=[tex]\frac{5\pi ^2}{4}=12.34 rad/s[/tex]

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