Solved papers for JEE Main & Advanced JEE Main Paper (Held On 12 May 2012)

done JEE Main Paper (Held On 12 May 2012) Total Questions - 2

• question_answer1) Two bodies A and B of mass m and 2m respectively are placed on a smooth floor. They are connected by a spring of negligible mass. A' third body C of mass m is placed on the floor. The body C moves with a velocity \[{{v}_{0}}\] along the line joining A and B and collides elastically with A. At a certain time after the collision it is found that the instantaneous velocities of A and B are same and the compression of the spring is \[{{x}_{0}}\]. The spring constant k will be   JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[m\frac{v_{0}^{2}}{x_{0}^{2}}\]                             
  done clear
  B)
                         \[m\frac{{{v}_{0}}}{2{{x}_{0}}}\]
  done clear
  C)
                         \[2m\frac{{{v}_{0}}}{{{x}_{0}}}\]                              
  done clear
  D)
                         \[\frac{2}{3}m{{\left( \frac{{{v}_{0}}}{{{x}_{0}}} \right)}^{2}}\]
  done clear
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• question_answer2) A spring is compressed between two blocks of masses \[{{m}_{1}}\] and \[{{m}_{2}}\] placed on a horizontal frictionless surface as shown in the figure. When the blocks are released, they have initial velocity of \[{{v}_{1}}\] and \[{{v}_{2}}\] as shown. The blocks travel distances \[{{x}_{1}}\] and \[{{x}_{2}}\] respectively before coming  to rest. The ratio \[\left( \frac{{{x}_{1}}}{{{x}_{2}}} \right)\] is     JEE Main Online Paper (Held On 12 May 2012)
  A)
  \[\frac{{{m}_{2}}}{{{m}_{1}}}\] 
  done clear
  B)
                         \[\frac{{{m}_{1}}}{{{m}_{2}}}\]
  done clear
  C)
                         \[\sqrt{\frac{{{m}_{2}}}{{{m}_{1}}}}\]                    
  done clear
  D)
                         \[\sqrt{\frac{{{m}_{1}}}{{{m}_{2}}}}\]
  done clear
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