Angular and linear velocity question

  • #1

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I have a question, let’s say I’m holding a long piece of wood such as. 1’ x 6’ plank and I’m rotating it in a circle by spinning around with my hands extended, I suddenly let go, what happens to the velocity of the wood since every point on the wood that is a different distance from the center of rotation is traveling at a different linear speed. I’m assuming the wood will try to spin around it’s center of mass but how would that work when the wood is let go of has all different velocities . Was just curious because when reading about physics of centripetal force it says the object will move about in a straight line but I’m assuming that’s for small objects likes balls and such, nothing is ever discussed when you have an object that is long and is spinning and let go of. Maybe I should try spinning a board but since I don’t have a safe place to do this I figured I would ask.
 

Answers and Replies

  • #2
jbriggs444
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The object's center of mass will continue in a straight line. The various pieces start with various velocities relative to the center of mass that amount to a rotation about that center.
 
  • #3
kuruman
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The wood is a rigid body. Although pieces on it have different linear velocities, they have a common angular velocity about the center of mass at all times. When you let go, these pieces will rotate about the CM while the CM will describe projectile motion in general or will move in a straight line if gravity is not acting on it.
Was just curious because when reading about physics of centripetal force it says the object will move about in a straight line but I’m assuming that’s for small objects likes balls and such, ...
You are assuming correctly.
 
  • #4
Bandersnatch
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Check out videos from hammer throw competitions. They're doing the experiment for you.
 

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