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Examples of Conservation of Angular Momentum
A diver can change his/her rate of rotation during the dive, by varying the distribution of mass.  
   
The diver starts out with low angular velocity with body straight and arms outstretched.  
 
   
   
   
   
The distribution of mass is then changed (the arms and legs are brought nearer to centre of mass) in order to decrease the moment of inertia and so increase the angular velocity.  
   
   
   
   
Finally, when near the water, the diver stretches arms and legs out again to decrease the angular velocity, to enter the water smoothly (before being eaten).  
   
   
   
And... it's not only human beings who make use of this principle.  
   
 
If a cat falls from an initially upside down position, it will usually be able to land on its feet.  
 
 
With its legs arranged as shown here, the back part of the cat's body has a greater moment of inertia.  
This allows the cat to rotate the front half of its body.  
 
 
 
 
 
 
Now the arrangement of the legs is inversed (the tail also helps) and the back part can be rotated.  
 
 
 
 
 
   
 
 
These procedures are repeated as many times as necessary in order to finish upright.  
 
 
   
However... remember that many animals do not have this ability...  
   
   
No cats were harmed during the writing of this page... elephants, maybe...  
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