Angular velocity and period of a disc rotating about point on circumference

In summary, the problem is to find the angular velocity and period of oscillation of a solid disc of mass m and radius R rotating about a point on its circumference. The only given information is the moment of inertia, which is equal to half of the mass times the square of the radius, and the approximation that the sine of an angle is approximately equal to the angle itself. There is also a diagram provided by the professor. The student is unsure of how to approach the problem, as it seems to involve both simple harmonic motion and rotational motion. The student is also unsure if the problem is asking for the velocity or the angular velocity, and notes that there is a discrepancy between the title and the actual problem statement in terms of the point of
  • #1
rcw110131
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0

Homework Statement



Find the angular velocity and period of oscillation of a solid disc of mass m and radius R about a point on it’s surface.

Homework Equations



?

The Attempt at a Solution



This is really giving me trouble because it seems like a SHO problem mixed with a rotational motion problem, and I don't even know where to start. Any help would be greatly appreciated :confused: .
 
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  • #2
Is that all you are given, exactly the way the problem is stated? That's exactly like "find the velocity of an object moving in a straight line"! An object can move with almost any velocity and can rotate with almost any angular velocity. Oh, and in your title you say "rotating about point on circumference" but your problem says "about a point on it’s surface". Those are not at all the same thing. Which is correct?
 
  • #3
HallsofIvy said:
Is that all you are given, exactly the way the problem is stated? That's exactly like "find the velocity of an object moving in a straight line"! An object can move with almost any velocity and can rotate with almost any angular velocity. Oh, and in your title you say "rotating about point on circumference" but your problem says "about a point on it’s surface". Those are not at all the same thing. Which is correct?

Yes, the disc pivots around a point on its circumference, according the very unhelpful diagram my professor gave me. She's also Sri Lankan so her English isn't great, which would explain the "surface" part. And the question is a direct quote, that's all I have. :confused: ^ 100000

EDIT: sorry, she also gave us: "I = (mR^2)/2, Assume sin(theta)≈theta"
 

Question 1: What is angular velocity?

Angular velocity is a measurement of how quickly a disc is rotating about an axis. It is typically measured in radians per second.

Question 2: How is angular velocity calculated?

Angular velocity is calculated by dividing the change in angle over time. The formula is: ω = Δθ/Δt, where ω is the angular velocity, Δθ is the change in angle, and Δt is the change in time.

Question 3: What factors affect the angular velocity of a rotating disc?

The angular velocity of a rotating disc is affected by its moment of inertia, the applied torque, and any external forces acting on the disc.

Question 4: What is the period of a disc rotating about a point on its circumference?

The period of a disc rotating about a point on its circumference is the time it takes for the disc to make one full rotation. It is calculated by dividing the total time by the number of rotations.

Question 5: How is the period related to the angular velocity?

The period and angular velocity are inversely proportional. This means that as the angular velocity increases, the period decreases and vice versa. This relationship is described by the formula: T = 2π/ω, where T is the period and ω is the angular velocity.

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