Solved papers for JEE Main & Advanced JEE Main Online Paper (Held On 23 April 2013)

done JEE Main Online Paper (Held On 23 April 2013) Total Questions - 3

• question_answer1)                 A particle of mass 2 kg is moving such hat at time t, its position, in meter, is given by \[\overset{\to }{\mathop{\operatorname{r}}}\,(\operatorname{t})=5\hat{i}-2{{\operatorname{t}}^{2}}\hat{j}.\]The angular momentum of the particle at \[\operatorname{t}=2s\] about the origin in kg \[{{\operatorname{m}}^{-2}}\]\[{{\operatorname{s}}^{-2}}\] is :     [JEE Main Online Paper ( Held On 23  April 2013 )
  A)
  \[-80\hat{k}\]
  done clear
  B)
                         \[\left( 10\hat{i}-16\hat{j} \right)\]
  done clear
  C)
                         \[-40\hat{k}\]                   
  done clear
  D)
                         \[40\hat{k}\]­­
  done clear
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• question_answer2)                 A boy of mass 20 kg is standing on a 80 kg free to move long cart. There is negligible friction between cart and ground. Initially, the boy is standing 25 m from a wall. If he walks 10 m on the cart toward the wall, then the final distance of the boy from the wall will be:     [JEE Main Online Paper ( Held On 23  April 2013 )
  A)
                    15 m                   
  done clear
  B)
                                           12.5 m
  done clear
  C)
                                           15.5 m                                
  done clear
  D)
                                           17 m
  done clear
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• question_answer3) A body of mass 'm' is tied to one end of a spring and whirled round in a horizontal plane with a constant angular velocity. The elongation in the spring is 1 cm. If the angular velocity is doubled, elongation in the spring is 5 cm. The original length of the spring is:     JEE Main Online Paper ( Held On 23  April 2013 )
  A)
  15 cm                 
  done clear
  B)
  12 cm
  done clear
  C)
  16 cm                 
  done clear
  D)
  10 cm
  done clear
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