General
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Physics-

Two small particles of equal masses start moving in opposite directions from a point A in a horizontal circular orbit. Their tangential velocities are vand 2 v, respectively, as shown in the figure. Between collisions, the particles move with constant speeds. After making how many elastic collisions, other than that at A, these two particles will again reach the point A

Physics-General

  1. 4    
  2. 2    
  3. 1    
  4. 3    

    Answer:The correct answer is: 2Let initially particle x is moving in anticlockwise direction and y in clockwise direction
    As the ratio of velocities of xand y particles are fraction numerator v subscript x end subscript over denominator v subscript y end subscript end fraction equals fraction numerator 1 over denominator 2 end fraction, therefore ratio of their distance covered will be in the ratio of 2 blank colon 1. It means they collide at point B

    After first collision at B, velocities of particles get interchanged, i. e., x will move with 2 v and particle y with v
    Second collision will take place at point C. Again at this point velocities get interchanged and third collision take place at point A
    So, after two collision these two particles will again reach the point A

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