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Mmarzipan
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Homework Statement
A ball A is rotating on a table with an angular velocity ω about its vertical axis. An identical ball B collides with the ball A elastically. After collision the ball A starts sliding over the table. The coefficient of friction is µ. Find:
1) the angle α between the angular velocity vector of the ball A and the vertical for any moment of time before the ball starts rolling
2) the time instant when ball A starts rolling
3)what happens with the angular velocity of A after it starts to roll
Homework Equations
Momentum is convserved?
The Attempt at a Solution
For the first question, the answer seems to easy - the angular velocity axis should be always vertical, that's said in the text as well.
For the second one I tried many ways, conservation of energy and conservation of momentum, but there's no information about the initial and final velocity of the second ball so I'm not sure. Should I use integration?
Third should be easy too - the answer is that it stays the same (in ideal conditions).