An object of mass $10 \mathrm{~kg}$ is released from rest in a liquid. If the object moves a distance of $2 \mathrm{~m}$ while sinking in time duration of $1 \mathrm{~s}$, then the mass of the liquid displaced by the submerged object is $\left(\right.$ Acceleration due to gravity $=10 \mathrm{~m} \mathrm{~s}^{-2}$ )

• A

  $5 \mathrm{~kg}$
• Correct answer
  B

  $6 \mathrm{~kg}$
• C

  $3 \mathrm{~kg}$
• D

  $4 \mathrm{~kg}$

Solution

We have, $\mathrm{S}=\frac{1}{2} \mathrm{at}^2 \Rightarrow 2=\frac{1}{2} \times \mathrm{a} \times 1^2 \Rightarrow \mathrm{a}=4 \mathrm{~m} / \mathrm{s}^2$
Now, $m g-F_B=m a$ $F_B=m g-m a=10 \times 10-10 \times 4=60 N$ $=6 \mathrm{~kg}$ weight So, mass of liquid displaced $=6 \mathrm{~kg}$

Hence, the correct answer is option: 'B'.