Fraud

This one might be a common question i guess, but not common enough!

A uniform rod of mass 7 kg and length 120 cm is hinged at one end. A particle of mass 2 kg travelling with a speed 15 m/s collides with the rod at a distance x from the center of mass of the rod such that the reaction force at the hinge is zero.

Find x.

Click here for the solution.

15 comments:

  1. AnonymousJune 10, 2011 at 6:38 PM

    What kind of a collision is it between the ball and the rod?

    ReplyDelete
  2. AnujJune 10, 2011 at 8:05 PM

    it can be of any type: 'e' can be anything b/w 0 to 1.

    ReplyDelete
  3. AnonymousJune 10, 2011 at 8:52 PM

    gravity consider karni hai?

    ReplyDelete
  4. AnujJune 10, 2011 at 9:07 PM

    gravity cannot play any role here

    ReplyDelete
  5. AnonymousJune 10, 2011 at 10:45 PM

    i am getting around 9cm as the answer..but the judge question feature is not accepting it..

    btw the second anonymous was some1 else :P

    ReplyDelete
  6. RohinJune 11, 2011 at 2:37 AM

    20

    ReplyDelete
  7. MayankJune 11, 2011 at 9:19 AM

    Easy one...

    ReplyDelete
  8. AnonymousJune 11, 2011 at 5:57 PM

    Since no external impulse is acting on the rod-ball system during collision we can apply conservation of momentum
    also we can apply conservation of angular momentum about hinge
    2 eqns and 2 unknowns viz. w and x [e=0]
    but i am getting 9cm...

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  9. Shivanker GoelJune 12, 2011 at 7:43 AM

    @Anonymous: even by ur own method, the answer is 20 cm, and not 9 cm..

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  10. AnonymousJune 13, 2011 at 1:24 AM

    @Anonymous:Please post your equations as well.

    ReplyDelete
  11. rishabhJune 13, 2011 at 1:54 PM

    i got the answer but why did bhaiya has mentioned it fraud

    ReplyDelete
  12. ShivankerJune 13, 2011 at 10:47 PM

    u will be answered soon rishabh.. :D

    ReplyDelete
  13. AnonymousJune 13, 2011 at 11:32 PM

    plz post the correct solution ..

    ReplyDelete
  14. ShivankerJune 15, 2011 at 12:05 PM

    the post has been updated with the link to the solution..

    ReplyDelete
  15. AnujJune 15, 2011 at 5:53 PM

    here's the same question, and more comments and solutions:

    http://anujkalia.blogspot.com/2010/03/gong.html#comments

    ReplyDelete

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