Angular acceleration of a computer disk

[JSapit]

Homework Statement

During normal operation, a computer's hard disk spins at 5400 rpm. If it takes the hard disk 8.4 s to reach this angular velocity starting from rest, what is the average angular acceleration of the hard disk in rad/s2?

Homework Equations

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The Attempt at a Solution

I don't even know where to start. Physics is not my strong point, and I definitely do not like angular physics problems.

 

[blochwave]

See your other topic where I just posted my generic rotational motion advice

With that in mind, remember that 2pi radians/second = 1 revolution per second so you can convert 5400 rpm to rad/sec

So similar to the other problem you have "distance", time, and initial "velocity"(ie angle traveled, time, and initial angular velocity)

 

[Moetasim]

I can understand your frustration with angular physics problems. However, let me try to break down the problem for you.

Firstly, we need to define a few key terms. Angular acceleration is the rate of change of angular velocity, which is the rotational speed of an object. In this case, the object in question is a computer's hard disk.

Next, we need to understand the units involved in this problem. Rotational speed is measured in revolutions per minute (rpm), while angular acceleration is measured in radians per second squared (rad/s2). This means we will need to convert the given rotational speed of 5400 rpm into radians per second (rad/s).

To do this, we can use the conversion factor of 2π radians = 1 revolution. Therefore, 5400 rpm can be converted to 5400/60 = 90 revolutions per second. Multiplying this by 2π gives us the angular velocity in rad/s, which is approximately 565.48 rad/s.

Now, we can use the formula for average angular acceleration, which is given by:

average angular acceleration = (final angular velocity - initial angular velocity) / time taken

In this case, the final angular velocity is 565.48 rad/s (as we calculated above), the initial angular velocity is 0 (since the hard disk starts from rest), and the time taken is 8.4 seconds. Substituting these values into the formula, we get:

average angular acceleration = (565.48 rad/s - 0) / 8.4 s = 67.44 rad/s2

Therefore, the average angular acceleration of the hard disk is 67.44 rad/s2. I hope this explanation helps you understand the problem better. Remember, practice makes perfect, so keep working on your angular physics problems and you will become more comfortable with them.