Radius and centripetal relation

AI Thread Summary
The discussion revolves around the relationship between centripetal force, radius, and acceleration in circular motion. The original poster is confused about why centripetal force is expressed as 2a instead of 2/a, given that the radius is twice as long. They note that radius is inversely proportional to acceleration, leading to questions about the proportionality of radius and acceleration. Another participant clarifies that with a constant angular velocity, using the expression for acceleration simplifies the problem. Ultimately, it is established that both speed and radius change, affecting the calculations of centripetal force.
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Homework Statement


the file given

Homework Equations



F=mv^2/r

The Attempt at a Solution


I do not understand why the centripetal force is 2a and not 2/a since the radius of X is twice longer.

When I use the equation above, raidius is inversely proportional to the acceleration.

Is radius proportional to the accerlation? Then why it is?[/B]


 

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Both speed and radius change. And I don't see how you would place the a in the denominator. That doesn't even give an acceleration in terms of units.
The angular velocity is constant. There is an expression for the acceleration that uses the angular velocity, that makes the problem easier.
 
so
mfb said:
Both speed and radius change. And I don't see how you would place the a in the denominator. That doesn't even give an acceleration in terms of units.
The angular velocity is constant. There is an expression for the acceleration that uses the angular velocity, that makes the problem easier.
sorry i got a/2 hahah
 
SUSUSUSUSUSUSUSU said:
so

sorry i got a/2 hahah

when i use 2R, the equation will be mv^2/2R which is a/2. this is what i have got
 
The speed changes as well, don’t forget that.
 
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