Question

A body having volume $V$ and density $\rho$ is attached to the bottom of a container as shown. Density of the liquid is $d$ $(>\rho )$. Container has a constant upward acceleration $a$. Tension in the string is:

• A. $V[Dg-\rho (g+a)]$
• B. $V(g+a)(d-\rho )$
• C. $V(d-\rho )g$
• D. none

Answer 1

The correct option is B $V(g+a)(d-\rho )$

Note that the acceleration has an effect on both upthrust and weight
Weight experienced by the mass =$\rho V(g+a)$
Upthrust experienced by the mass =$dV(g+a)$
Tension experienced by the string =$Upthrust-Weight$
=$V(g+a)(d-\rho )$