Angular acceleration and angular velocity

Click For Summary

Homework Help Overview

The discussion revolves around calculating the angular acceleration and angular velocity of a rotating object, specifically a 4 kg object moving in a circular path with a radius of 3 m over a time span of 6 seconds.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply formulas related to angular acceleration and velocity but questions the correctness of their calculations. Some participants clarify the definitions of angular acceleration and centripetal acceleration, noting the inconsistency in the original poster's approach.

Discussion Status

Participants are actively engaging in clarifying concepts, particularly around the definitions and calculations of angular acceleration and velocity. There is acknowledgment that the original poster's understanding may need refinement, especially regarding the assumptions about angular acceleration.

Contextual Notes

There is a lack of information regarding how angular velocity changes over time, which affects the discussion on angular acceleration. The participants note that without this information, angular acceleration may be considered zero.

John78
Messages
21
Reaction score
0

Homework Statement



Calculate the angular acceleration and angular velocity of a 4 kg object rotating in a circle of 3 m radius in a time of 6 s.

Homework Equations





The Attempt at a Solution



Angular acceleration = ω2*r

C=2∏r= 2*3.14*3=18.84
360°/57.3°=6.28 rad/s
6.28/6= 2.09 rad/sec

Angular acceleration= (2.09)2*3=12.54??


Angular velocity= angular displacement/time ?



I just want to check whether my working is correct or not.
 
Physics news on Phys.org
Nope.Its not right.

Remember, angular acceleration is dw/dt.

The acceleration w^2*r is centripetal accelwration.

Infact writing angular acceleration as w^2*r is dimemsionally inconsistent.


As nothing had been told about how w changes with time nothing can be said about angular acceleration.

In such cases w is assumed to be constant making angular acceleration 0
 
angular acceleration = 0


what about angular velocity?
 
Hi John78! :smile:
John78 said:
angular acceleration = 0

Correct.
what about angular velocity?

Your formula …
Angular velocity= angular displacement/time
… is fine :smile:
 

Similar threads

Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 8 ·
Replies
8
Views
1K
Replies
8
Views
2K
Replies
67
Views
4K
  • · Replies 17 ·
Replies
17
Views
1K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K