Solved papers for JEE Main & Advanced JEE Main Paper (Held On 11 April 2015)

done JEE Main Paper (Held On 11 April 2015) Total Questions - 3

• question_answer1) A large number (n) of identical beads, each of mass m and radius r are strung on a thin smooth rigid horizontal rod of length \[L(L>>r)\] and are at rest at random positions. The rod is mounted between two rigid supports (see figure). If one of the beads is now given a speed v, the average force experienced by each support after a long time is (assume all collisions are elastic) : [JEE Main Online Paper (Held On 11 April 2015)]  
  A)
  \[\frac{m{{\upsilon }^{2}}}{L-nr}\]
  done clear
  B)
  \[\frac{m{{\upsilon }^{2}}}{L-2nr}\]
  done clear
  C)
  \[\frac{m{{\upsilon }^{2}}}{2(L-nr)}\]
  done clear
  D)
   zero
  done clear
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• question_answer2) A uniform thin rod AB of length L has linear mass density \[\mu (x)=a+\frac{bx}{L},\]where x is measured from A. If the CM of the rod lies at a distance of \[\left( \frac{7}{12}L \right)\]from A, then a and b are related as : [JEE Main Online Paper (Held On 11 April 2015)]  
  A)
   a = b
  done clear
  B)
   a = 2b
  done clear
  C)
   2a = b
  done clear
  D)
   3a = 2b
  done clear
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• question_answer3) A particle of mass 2 kg is on a smooth horizontal table and moves in a circular path of radius 0.6 m. The height of the table from the ground is 0.8 m. If the angular speed of the particle is 12 rad \[{{\text{s}}^{\text{-1}}}\text{,}\]the magnitude of its angular momentum about a point on the ground right under the centre of the circle is : [JEE Main Online Paper (Held On 11 April 2015)]  
  A)
  \[\text{8}\text{.64}\,\text{kg}\,{{\text{m}}^{\text{2}}}{{\text{s}}^{\text{-1}}}\]
  done clear
  B)
  \[\text{11}\text{.52}\,\text{kg}\,{{\text{m}}^{\text{2}}}{{\text{s}}^{\text{-1}}}\]
  done clear
  C)
  \[\text{14}\text{.4}\,\text{kg}\,{{\text{m}}^{\text{2}}}{{\text{s}}^{\text{-1}}}\]
  done clear
  D)
  \[\text{20}\text{.16}\,\text{kg}\,{{\text{m}}^{\text{2}}}{{\text{s}}^{\text{-1}}}\]
  done clear
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