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Homework Help: Angular velocity (check it out n tell me what u guys think)

  1. Sep 21, 2005 #1
    angular velocity......(check it out n tell me what u guys think)

    hello ppl.....

    consider this problem.....

    u could refer 2 resnick n halliday 5th edition, the 3rd author is krane. chapter 10, problem no. 8.

    theres a disc thats rotating about a horizontal axis with angular velocity 'w'. a small mass 'm' just chips off n flies vertically upwards as the disc is rotationg, what is the final angular velocity of the disc.

    now when the chip flies off, it has a linear vel= r.w
    is it correct to assume it also has an instantaneous angular velocity= w ?

    also refer problem 2 in the same chapter, it says 2 particles (mass 'm' each) r moving in opp directions with speed 'v' along parallel lines sep. by a dist. 'd' find the total angular momentum of system abt any origin.

    the second problem requires us to find angular momentum of particles which r moving in st lines. r v req. to make a hypothetical assumption n find the ans. or do the actually have angular velocity.

    on similar lines. if we assume the mass 'm' that chips off to have an angular velocity then the result obtained is that the disc continues to rotate with the same angular velocity. does that mean everytime we remove a portion of mass frm the disc, it continues to rotate with same ang. vel. 'w'?

    plz just answer the question ......do all bodies moving with linear velocities have ang. vel w.r.t a fixed point???

    waiting 4 an answer.........

  2. jcsd
  3. Sep 21, 2005 #2
    For the first problem, you'll want to note that angular momentum is conserved. If the piece flew off, you have a little change in the moment of inertia, which will result in a change in angular velocity.

    Try showing some effort on the problem, #2 is hard to decipher.
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