The tension in a string holding a solid block below the surface of a liquid (of density greater than that of solid) as shown in figure is `T_(0)` when the system is at rest. What will be the tension in the string if the system has an upward acceleration a?
.

Options

A. `T(1-a/g)`
B. `T(1+a/g)`
C. `T(a/g-1)`
D. `a/gT`

Answer

B

Explanation

Let `v` be the volume of the solid block of density `rho.` Let `rho_(1)` be the density of water.Weight of body `=vrhog`. When the body is immersed in water.
Tension in the string`=` Upward thrust `-` Weight of the body
`implies T=vrho_(1)g-vrhog=vg(rho_(1)-rho_(2))`
When the lift is moving upwards with acceleration a the tension in the string is `T=v(rho_(1)-rho)(g+a)`
From eqn i and ii `T=T_(0)(1+a/g)`