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Optics (Reflection of Light)

  • Thread starter DriggyBoy
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  • #1
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A gun of mass 'M' fires a bullet of mass 'm' with a horizontal velocity 'v'. The gun is fitted with a plane mirror facing towards the receding bullet. Find the velocity relative to its image just after the gun is fired.
 

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  • #2
Orodruin
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The above is simply the problem statement. What are your thoughts on the problem? Where do you get stuck?
 
  • #3
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Cannot proceed much....law of conservation of momentum needs to be applied i guess
 
  • #4
adjacent
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Cannot proceed much....law of conservation of momentum needs to be applied i guess
So apply it and show what you get.
 
  • #5
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I have solved but not sure if its correct. I have considered the velocity of the gun to be M. Now by conservation of linear mmntum, mv=MV.....therefore V = mv/M
relative velocity wrt gun = v + V = mv/V + v = (m/M + 1)v
Therefore relative vel wrt image = 2*v(m/M + 1) = 2v(m/M + 1) [ since image dist = objct dist for plane mirror ]
Not sure....just check it.....thanks in advance :)
 
  • #6
NascentOxygen
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That's the general idea, but you would lose marks for lack of rigor (and multiple typos!).

mv = -MV
 

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