U. Phys

posted by .

What is the angular momentum of a 3.7kg uniform cylindrical grinding wheel of radius 25cm when rotating at 1500rpm?


How much torque(in magnitude) is required to stop it in 5.0s?

Could you explain this in detail, I don't really understand torque and momentum well.

  • U. Phys -

    You need to separate linear motion from rotational.

    Read in two columns
    mass kg...........momentofinertia kg*m^2
    displacement m...angular displacement rad
    velocity m/s ....ang velocity rad/s^2
    acceleration m/s^2.ang acc rad/s^2

    and finally, memorize this
    tangential velocity on a curve= radius*ang velocity

    Now your question.
    ang momentum=I*w
    (that is ang momentum is momentofinertia * angular velocity)
    So you need I for a solid disk, make you a convenient card with common shapes..http://en.wikipedia.org/wiki/List_of_moments_of_inertia
    Using thin disk model, I= mr^2/2
    ang momentum= mr^2/2 * 1500rev/min*1min/60sec*2PIrad/rev

    b) Torque= I*angacceleration= I*(wf-wi)/time= mr^2/2(-1500*2PI/60)

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics

    What is the angular momentum of a 2.4 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1800 rpm?
  2. physics help please!!!

    What is the angular momentum of a 2.5 kg uniform cylindrical grinding wheel of radius 19 cm when rotating at 1200 rpm?
  3. PHYSICS

    What is the angular momentum of a 2.7 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1600 rpm?
  4. Physics

    An electric motor rotating a workshop grinding wheel at a rate of 95 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.40 rad/s2. (a) How long does it take for the grinding wheel …
  5. Physic

    An electric motor rotating a workshop grinding wheel at a rate of 114 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.10 rad/s2. (a) How long does it take for the grinding wheel …
  6. physics

    An electric motor rotating a workshop grinding wheel at a rate of 9.80 101 rev/min is switched off. Assume the wheel has a constant negative angular acceleration of magnitude 2.00 rad/s2. (a) How long does it take for the grinding …
  7. Physic Angular momentum and torque

    What is the angular momentum of a 1.0kg uniform cylindrical grinding wheel of radius 19cm when rotating at 1700rpm ?
  8. physic angular momentum and torque

    What is the angular momentum of a figure skater spinning at 2.7rev/s with arms in close to her body, assuming her to be a uniform cylinder with a height of 1.6m , a radius of 14cm , and a mass of 50kg How much torque is required to …
  9. physics

    What is the angular momentum of a 2.43 kg uniform cylindrical grinding wheel of radius 12.5 cm when rotating at 1600 rpm?
  10. GENERAL PHYSICS

    An electric motor rotating a grinding wheel at 100 rev/min is switched off. With constant negative angular acceleration of magnitude 2rad/second squared, how long does it take the wheel to stop?

More Similar Questions