When Does a Bob Attached to a String Become Slack?

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A bob attached to a string becomes slack when the tension in the string (T) reaches zero. This occurs when the gravitational force component (mg cos θ) equals the centripetal force required for circular motion (mv²/r). The discussion emphasizes that the angle (θ) must be considered, particularly whether it remains below or exceeds 90 degrees. If T=0, it indicates that the bob is no longer in circular motion and the relationship between θ and velocity (v) is critical. Understanding these dynamics is essential for analyzing the motion of the bob.
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When does a bob attached to a string become slack?When mgcos@ = mv^2/r?
 
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When doing what? You're going to have to provide a bit more information about what the bob on the string is doing?
 
atavistic said:
When does a bob attached to a string become slack?When mgcos@ = mv^2/r?

It depends if you are restricting the angle to be below 90 degrees or if you may go above.
The equation (for theta smaller or equal to 90 degrees) is

T - mg cos theta = m v^2/R

The rope becomes slack if T=0.

what can you say about theta and v in that case?
 

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