physics

posted by .

Your hard drive can spin up to 7500 rpm from rest in 5 s. If your hard drive's mass is 40 g and its radius is 2.5 in, what is the force applied to the drive if the force is applied at a point 0.25 in from the center? Assume the drive is a solid, uniform disk with I = (1/2)mr2, and assume the force is applied tangentially.

is my work correct

7500 rpm * 2pi* (1/60sec) = 785.4 rad/s
angular accel = (785.4-0)/5 = 157rad/s^2

F = mass*angular acceleration*radius
F =0.04Kg * 157rad/s^2 * (0.0635m)
F =0.4N

  • physics -

    The angular acceleration is correct.
    The Greek symbol "alpha" is usually used for that.

    For the force F, you need to use the angular acceleration equation:
    Torque L = F*r = I*(alpha)
    = (Moment of Inertia)*(Angular acceleration) = (1/2) M R^2 * alpha

    F = (1/2)(R^2/r)*M*(alpha)

    R is the disc radius and r is the radial distance to the point of application of the force

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    Under the influence of its drive force, a snowmobile is moving at a constant velocity along a horizontal patch of snow. When the drive force is shut off, the snowmobile coasts to a halt. The snowmobile and its rider have a mass of …
  2. Computer

    Your computer is running very slow. The LED light for the hard drive blinks nearly continually, indicating that the hard drive is spinning even when data is not being saved or read from the hard drive. Based on this scenario, what …
  3. Computer

    What is the standard configuration for a newly purchased hard drive?
  4. Computer Hardware

    Your computer fails to boot which has Vista as the operating system. You suspect that the problem is the hard drive, but you aren't sure. What can you do to prove that the problem is indeed the hard drive?
  5. psychology

    20 You are trying to boot your computer but your computer keeps displaying a message after the POST that says “'invalid specification”. What does the error mean?
  6. computer Science

    20 You are trying to boot your computer but your computer keeps displaying a message after the POST that says “'invalid specification”. What does the error mean?
  7. computer Science

    20 You are trying to boot your computer but your computer keeps displaying a message after the POST that says “'invalid specification”. What does the error mean?
  8. Physics

    A computer hard drive rotates at 5400 revolutions per minute. Starting from rest, what torque will get the hard drive up to that speed in just 150 revolutions?
  9. Physics help please

    You are a 70kg astronaut floating at rest in zero gravity holding your laptop. Your hard drive turns on (increasing from 0 to 5400 rpm). How fast do you spin in rad/s?
  10. physics question (with more information)

    You are a 70kg astronaut floating at rest in zero gravity holding your laptop. Your hard drive turns on (increasing from 0 to 5400 rpm). Approximate yourself as a uniform sphere of radius 30cm. How fast do you spin in rad/s?

More Similar Questions