Number of revolutions a disk has made after a given time

In summary, a computer hard disk starts from rest and undergoes a constant angular acceleration of 218 rad/s^2 until it reaches its final angular speed of 6660rpm. After 10.1s, the disk has made a certain number of revolutions which can be calculated using the given information. The problem can be solved using the concept of constant angular acceleration.
  • #1
FGCUgrl11
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1. A computer hard disk starts from rest, then speeds up with angular acceleration of 218 rad/s^2 until it reaches its final angular speed of 6660rpm. How many revolutions has the disk made 10.1s after it starts up?



3. The Attempt at a Solution .
I have no idea how to find the number of revolutions in the time given with what appers to be a changing acceleration rate. I am unsure what is going on or how to solve this problem. Please help!
 
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  • #2
FGCUgrl11 said:
1. A computer hard disk starts from rest, then speeds up with angular acceleration of 218 rad/s^2 until it reaches its final angular speed of 6660rpm. How many revolutions has the disk made 10.1s after it starts up?
3. The Attempt at a Solution .
I have no idea how to find the number of revolutions in the time given with what appers to be a changing acceleration rate. I am unsure what is going on or how to solve this problem. Please help!


this is a constant angular acceleration problem. does that help? It has that constant acceleration until it reaches that speed, and after that, the acceleration equals zero.
 

1. How is the number of revolutions of a disk calculated?

The number of revolutions of a disk is calculated by dividing the distance the disk has traveled by the circumference of the disk. This gives the number of full revolutions. Any partial revolutions can be calculated by multiplying the decimal portion of the result by the circumference.

2. What is the relationship between time and the number of revolutions of a disk?

The relationship between time and the number of revolutions of a disk depends on the speed at which the disk is rotating. Generally, the longer the time, the more revolutions the disk will make. This relationship can be expressed mathematically as revolutions = (speed * time) / circumference.

3. How does the size of the disk affect the number of revolutions after a given time?

The size of the disk does not affect the number of revolutions after a given time, as long as the speed of rotation remains constant. This is because the number of revolutions is determined by the distance traveled and not the size of the disk.

4. Can the number of revolutions of a disk be negative?

No, the number of revolutions of a disk cannot be negative. Revolutions are a measure of the number of times the disk has rotated, and rotation is always in a positive direction. If the disk were to rotate in the opposite direction, it would be considered as a negative number of revolutions.

5. How can the number of revolutions of a disk be measured accurately?

The number of revolutions of a disk can be measured accurately by using a device called a tachometer. This device measures the rotational speed of the disk and can be calibrated to give a precise measurement of the number of revolutions. Another way to measure accurately is by using a stopwatch and recording the time it takes for a specific point on the disk to complete one full rotation.

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