A block of mass 1 kg and density `0.8g//cm^(3)` is held stationary with the help of a string as shown in figure. The tank is accelerating vertically upwards with an acceleration a `=1.0m//s^(2)`. Find

(a) the tension in the string,
(b) if the string is now cut find the acceleration of block.
(Take `g=10m//s^(2)` and density of water `=10^(3)kg//m^(3))`.

Options

A. `T=2.2N`
B. `T=2.75N`
C. `T=3N`
D. `T=2.4N`

Answer

B

Explanation

`F="upthrust force"=Vrho_(w)(g+a)`
`=(("mass of block")/("Density of block"))rho_(w)(g+a)`
`=(1)/(800)(1000)(11)=13.75N`
`F-T-W=ma,13.75-T-10=1(1)`
`T=2.75N`