Four particles are placed at the corners of a square of side 1m. At t=0, they start moving towards each other (each one moves towards its clockwise neighbor) with a velocity 2m/s.

After traveling half the distance to the center (where they would have collided), each of them doubles its speed.

After what time do the actually collide??

13 comments:

  1. piyush gargMarch 30, 2010 at 10:48 PM

    .375s if half distance means separation has turned to half

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  2. ♥◘○µ╦┬░Γ╪╬└↑φΦ╫╛◙«½╣↔⌐☺♠♦♣◘○March 30, 2010 at 10:52 PM

    This comment has been removed by the author.

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  3. Sambhav GuptaMarch 30, 2010 at 11:03 PM

    This comment has been removed by the author.

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  4. Sambhav GuptaMarch 30, 2010 at 11:09 PM

    sry i meant 3/8 seconds only

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  5. ankush sachdevaMarch 31, 2010 at 12:26 AM

    me too getting 3/8 sec

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  6. piyushMarch 31, 2010 at 10:45 AM

    3/8 sec.

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  7. AnujMarch 31, 2010 at 1:07 PM

    no, plz. do not assume that halving the distance makes the separation half.

    though the answer is correct, the assumption is not justified.

    either you PROVE it, or you adopt a better approach Piyush.

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  8. AnujMarch 31, 2010 at 1:09 PM

    and why do you people remove some of your posts..its interesting to see what all mistakes you made bfore arriving at the soln..

    as i have said bfore, some of these are real tough problems..no one expects you to solve them in the first attempt..

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  9. Rohan SharmaMarch 31, 2010 at 5:16 PM

    pendi bhaiya, ye kaisa ghatiya sawal hai.
    Isse badiya to main puch loon.

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  10. Sambhav GuptaMarch 31, 2010 at 6:38 PM

    hey whosoever this is...please mind ur language

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  11. AnujMarch 31, 2010 at 7:39 PM

    hi Sambhav..this is the same Rohan you see as Rohan Sharma (AIR 17)on VM site. He was just playing a prank on me..

    but i appreciate your concern! thanks!
    uska to muh band ho gaya...

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  12. piyushMarch 31, 2010 at 9:11 PM

    bhaiya plz see the center of rotation vala ques i have left a msg regarding my doubt thank u

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  13. rohanApril 1, 2010 at 5:06 PM

    here is the solution of this problem if anyone student except above how himself solve this problem needed. USE THE RELATIVE VELOCITY CONCEPT.THE RELATIVE VELOCITY OF EACH PARTICLE TILL THEY COVER HALF OF THE DISTANCE BEFORE THEY COLLIDE IS v m/sec. So after covering half of the distance the relative velocity with respect to the clockwise neighbour become 2v m/sec.so the total time of collide is 1/4+1/8=3/8

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