What is the Initial Angular Acceleration of a Disk Released from Rest?

AI Thread Summary
The initial angular acceleration of a disk released from rest can be calculated using the torque equation, Torque = Iα. The weight of the disk is determined to be 49 N, and the radius used for torque calculation is 0.3 m, resulting in a torque of 14.7 N·m. The moment of inertia must be adjusted using the Parallel Axis theorem since the axis of rotation is not through the center of mass. The correct moment of inertia is calculated as I = I_{CM} + MD^2, where I_{CM} is the moment of inertia for a solid disk. This adjustment leads to the accurate calculation of angular acceleration.
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A 5.0 kg, 60-cm-diameter disk rotates on an axle passing through one edge. The axle is parallel to the floor. The cylinder is held with the center of mass at the same height as the axle, then released.

What is the cylinder's initial angular acceleration?

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ok so this is what i think i should do:

Torque= I \alpha

and i need to find the F(weight)= mg = (5)(9.8) = 49 N
radius = .5(.6)= .3
Torque= Fd = 49(.3) = 14.7
14.7 = I \alpha
this is the part which i am not sure on, does I = .5 m r^2 = .5(5)(.3^2) = .225
14.7 .225 \alpha
\alpha = 65.33
but this answer is incorrect, and i do not know where i am making the mistake.
 
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please can someone help
 
Try using the Parallel Axis theorem to find the moment of inertia. This is needed because the axis of rotation is not through the centre of mass of the disk.

I = I_{CM} + MD^2

where I_{CM} is the moment of inertia for a solid disk, M is the mass of the disk and D is the distance from the centre of mass to the new axis.
 
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