Help needed to convert angular velocity to angular acceleration

AI Thread Summary
The discussion revolves around calculating angular acceleration given an angular velocity of 5 rad/s, mass of 4 kg, radius of 2 m, and a time period of 3 seconds for one revolution. Participants clarify that if the angular velocity is constant, the angular acceleration is zero. There is confusion regarding the relationship between angular and centripetal acceleration, with suggestions to convert angular velocity to tangential velocity for further calculations. Ultimately, it is emphasized that the provided data is inconsistent, as a time period of 3 seconds would yield an angular velocity of approximately 2 rad/s, not 5 rad/s. Accurate calculations require consistent data regarding motion parameters.
sherazi21st
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hi,

I've calculated
ω=5 rad/s

How can I calculate angular acceleration (α)
I've Mass, M=4Kg
Radius, R = 2m
and time taken by each single revolution, T=3sec.
 
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Unless you forgot to tell us something, the angular acceleration is zero!
 
I've only this data, what is missing?
 
sherazi21st said:
I've only this data, what is missing?
How the angular velocity is changing.

Are you sure you want angular acceleration, not centripetal acceleration?
 
I had also the same point but I got this data only. I thought there may be any method to convert this by either convert this ang. vel. to tang. vel. by rw and then it might be converted into angular acc. by using definition of centripetal acc. or something else if I'm not wrong.
 
sherazi21st said:
I had also the same point but I got this data only. I thought there may be any method to convert this by either convert this ang. vel. to tang. vel. by rw and then it might be converted into angular acc. by using definition of centripetal acc. or something else if I'm not wrong.
Angular acceleration is related to tangential acceleration, not centripetal acceleration. But all you gave us is an angular velocity.

You need to describe what you are being asked to find in more detail. What did you measure? What physics topic are you studying now?
 
Doc Al said:
How the angular velocity is changing.

Are you sure you want angular acceleration, not centripetal acceleration?

Can you tell me how will we calculate Centripetal acceleration? Just by converting w into v and then putting v in v^2/r. Am I correct?
 
Doc Al said:
Angular acceleration is related to tangential acceleration, not centripetal acceleration. But all you gave us is an angular velocity.

You need to describe what you are being asked to find in more detail. What did you measure? What physics topic are you studying now?

Dear, I'm studying Angular acceleration and angular velocity. I am given only radius of the horizontal circle in which a mass m is moving and completes one revolution in t seconds. I guess there is fault in the question.
 
sherazi21st said:
Can you tell me how will we calculate Centripetal acceleration? Just by converting w into v and then putting v in v^2/r. Am I correct?
Sure. You can also use this equivalent expression and save yourself the conversion: ac = ω2r
 
  • #10
sherazi21st said:
I am given only radius of the horizontal circle in which a mass m is moving and completes one revolution in t seconds.
Is it moving with constant speed, or does it start from rest (for instance)?
 
  • #11
Doc Al said:
Is it moving with constant speed, or does it start from rest (for instance)?

constant w
 
  • #12
sherazi21st said:
constant w
In that case, the angular acceleration is zero, as pointed out by russ_watters earlier.
 
  • #13
sherazi21st said:
hi,

I've calculated
ω=5 rad/s

How can I calculate angular acceleration (α)
I've Mass, M=4Kg
Radius, R = 2m
and time taken by each single revolution, T=3sec.

It's either T =3s OR w=5 rad/s.
You cannot have both for the same motion, with constant angular speed.

If T=3s, the angular velocity is about 2 rad/s.
 
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