2. Solved Papers
  3. WB JEE Medical

WB JEE Medical WB JEE Medical Solved Paper-2011

  • question_answer
    A stone of relative density K is released from rest on the surface of a lake. If viscous effects are ignored, the stone sinks in water with an acceleration of

    A)  \[g(1-K)\]                          

    B)  \[g(1+K)\]

    C)  \[g\left( 1-\frac{1}{K} \right)\]                 

    D)  \[g\left( 1+\frac{1}{K} \right)\]

    Correct Answer: C

    Solution :

                     The net force acting on the stone in a downward direction would be equal to \[F=V\sigma g-V\rho g,\]where m is the mass of the stone, the force acting downwards would be equal to \[V\sigma g\]due to its weight and the force acting upwards would be equal to \[V\rho g\]due to the buoyant force. Hence, we get \[F=V\sigma g-V\rho g=V\sigma g\left( 1-\frac{\rho }{\sigma } \right)\] \[=mg\left( 1-\frac{\rho }{\sigma } \right)=mg\left( 1-\frac{1}{K} \right)\]                 Thus,                     \[a=g\left( 1-\frac{1}{K} \right)\]


You need to login to perform this action.
You will be redirected in 3 sec spinner