Linear acceleration

1. Dec 2, 2007

MIA6

1. The problem statement, all variables and given/known data
A grinding wheel 0.35 m in diameter rotates at 2500rmp. What is the linear acceleration of a point on the edge of the grinding wheel?
For the linear acceleration, should it be atotal=atan+aR? Should we find both tangential acceleration and centripetal acceleration? But on the answer key, it's only centripetal acceleration. i dont' know why? But also I can not find tangential acceleration since I dont know the time. Hope you can help. thanks.

2. Dec 3, 2007

MIA6

Should we find both tangential and centripetal acceleration?

3. Dec 3, 2007

PhanthomJay

The wheel is rotating at constant angular velocity and constant tangential speed; ; therfore, it has no tangential acceleration, just radial (or centripetal) acceleration.

4. Dec 3, 2007

MIA6

How do you know it's constant angular velocity? Because it didn't say anything about acceleration of angular velocity?

5. Dec 4, 2007

PhanthomJay

It said it it is moving at 2500rpm. That is a constant angular velocity. If it was accelerating, it would have stated such, or at least made a veiled reference to it and given other data. It is like saying that a train is moving at 90mph......there is no reason to believe that the train is accelerating if it is not stated, that is, the 90 mph is assumed a constant speed.

6. Dec 5, 2007

MIA6

Ok. I got it. Thank you.