Is Velocity in Angular Motion Referring to Tangential or Angular Speed?

[oneplusone]

Hello,

I was solving some problems today. Sometimes the wording is something like this:

A ball attached to a string is traveling around a circular track with velocity $4$ m/s.
etc.


When it says the velocity is 4 m/s , does this mean the tangential, or angular velocity?
what is the distinction?

Thanks.

 

[A.T.]

When it says the velocity is 4 m/s , does this mean the tangential, or angular velocity?

Angular velocity is not measured in m/s, but in 1/s.

 

[JeweliaHeart]

If you are doing uniform circular motion (beginner's physics), most likely the problem is talking about avg. speed. For example, if the circle has a circumference of 5 m and the ball traveled around it in 2 seconds, the avg. speed is 2.5 m/s.

 

[oneplusone]

If you are doing uniform circular motion (beginner's physics)

Hello,

Yes, I'm doing beginners physics. I'm just having trouble finding if the object the problem mentions is traveling at a TANGENTIAL speed or ANGULAR speed. Like in the OP, how would you know that the velocity mentioned is tangential velocity?
Thanks.

 

[dipole]

Hello,

Yes, I'm doing beginners physics. I'm just having trouble finding if the object the problem mentions is traveling at a TANGENTIAL speed or ANGULAR speed. Like in the OP, how would you know that the velocity mentioned is tangential velocity?
Thanks.

The speed Jewelia worked out is the tangential speed. For uniform circular motion, the tangential speed is constant (as well as the angular speed).

Remember the relation between angular and tangential speeds: $v = \omega r$, so if it has units of $m/s$ it refers to the tangential speed.

 

[oneplusone]

Hello,
So does this mean whenever a problem says "an object moves with speed, s, in a circular path" the speed is the TANGENTIAL speed?I'm not sure how to phrase my question clearer.

 

[JeweliaHeart]

Dipole said it well, but here is a link just in case you need more help:
http://www.physicsclassroom.com/Class/circles/u6l1a.cfm

 

[JeweliaHeart]

Look at your units. Most likely, the problem is referring to tangential speed.

tangential speed is often written in meters/sec.

angular speed has units of radians/sec or degrees/sec.