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NEET2015PhysicsLaws of MotionActual

Three blocks A, B and C, of masses 4   kg ,   2   kg 1   kg and respectively, are in contact on a frictionless surface, as shown. If a force of 14   N is applied on the   4   kg block, then the contact force between A and B is:

Options

  1. A2   N
  2. B6   N
  3. C8   N
  4. D18   N

Correct answer

B. 6   N

Step-by-step solution

( aligned & F=M a= (M_a+M_b+M_c ) a & 14=(4+2+1) a=7 a & a=2 aligned ) Let (F^ ) be the contact force between ( A ~ &~ ~B ), ( aligned & F-F^ =4 a & 14-F^ =4 a=4 2 & F^ =6 N aligned )

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