U. Phys
posted by Taylor .
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.

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*(wfwi)/time= mr^2/2(1500*2PI/60)
Respond to this Question
Similar Questions

Physics
What is the angular momentum of a 2.4 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1800 rpm? 
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? 
PHYSICS
What is the angular momentum of a 2.7 kg uniform cylindrical grinding wheel of radius 12 cm when rotating at 1600 rpm? 
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 … 
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 … 
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 … 
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 ? 
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 … 
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? 
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?