# Average Angular Acceleration of a CD

• kmb11132
In summary, the conversation discusses finding the magnitude of the average angular acceleration of a CD, which has a playing time of 59.8 minutes and initial and final angular velocities of 460 and 202 rpm respectively. The solution involves converting the angular velocities to radians per second and using the formula for angular acceleration to calculate a value of -0.00753 rad/s^2. The use of scientific notation was expected for the answer to be accepted by the online grading system.
kmb11132

## Homework Statement

A CD has a playing time of 59.8 minutes. When the music starts, the CD is rotating at an angular speed of 460 revolutions per minute (rpm). At the end of the music, the CD is rotating at 202 rpm. Find the magnitude of the average angular acceleration of the CD. Express your answer in rad/s^2.

## Homework Equations

angular acceleration = change in angular velocity / change in time

## The Attempt at a Solution

460rpm / 60 * 2 * Pi = 48.17rad/s

202rpm / 60 * 2 * Pi = 21.15rad/s

time in s:
59.8min * 60 = 3588s

angular acceleration:
(21.15 - 48.17) / 3588 = -.00753rad/s^2

I'm really not sure why this is incorrect. I feel like I'm making a really obvious/face-palm type mistake.

It sounds like you are submitting this for online grading. For some reason these are known to have bugs in terms of accepting answers that are slightly off or in a different format from what the accepted answer is. I am always puzzled as to why they can't get it to act right.

You're exactly right. I'm using the WileyPlus system and it expected scientific notation without explicitly stating so.

## What is the definition of average angular acceleration?

The average angular acceleration of a CD is the rate of change of its angular velocity over a given time interval. It is a measure of how fast the CD is rotating or spinning.

## How is average angular acceleration calculated?

The average angular acceleration can be calculated by dividing the change in angular velocity by the change in time. This can be represented as: average angular acceleration = (final angular velocity - initial angular velocity) / time interval.

## What is the unit of measurement for average angular acceleration?

The unit of measurement for average angular acceleration is radians per second squared (rad/s²).

## Why is average angular acceleration important for CDs?

Average angular acceleration is important for CDs because it affects the playback quality and performance of the CD. Too much or too little angular acceleration can cause the CD to skip or distort the audio.

## What factors can affect the average angular acceleration of a CD?

The average angular acceleration of a CD can be affected by factors such as the speed at which the CD is spun, the weight and balance of the CD, and any external forces acting on the CD, such as friction or air resistance.

• Introductory Physics Homework Help
Replies
3
Views
888
• Introductory Physics Homework Help
Replies
3
Views
1K
• Introductory Physics Homework Help
Replies
9
Views
535
• Introductory Physics Homework Help
Replies
2
Views
5K
• Introductory Physics Homework Help
Replies
17
Views
2K
• Introductory Physics Homework Help
Replies
1
Views
3K
• Introductory Physics Homework Help
Replies
2
Views
936
• Introductory Physics Homework Help
Replies
9
Views
1K
• Introductory Physics Homework Help
Replies
32
Views
1K
• Introductory Physics Homework Help
Replies
19
Views
2K