• # question_answer A tank accelerates uniformly in upward direction with acceleration$1\,m/{{s}^{2}}$and contains water. A block of mass 1 kg and density 0.8 g/cc is held stationary inside the tank with the help of the string as shown in the figure. The tension in the string is [Take${{\rho }_{\text{water}}}=1000\,kg/{{m}^{3}}$and$g=10\,m/{{s}^{2}}$] A)  2.2 N                          B)  2.75 NC)  0                                D)  3.47 N

Free body diagram of block is as shown in the figure. Let us make observations from the frame of the tank. For equilibrium of the block, $V{{\rho }_{w}}(g+a)=T+mg+ma$ $\Rightarrow$$\frac{m}{800}\times 1000\times (10+1)=T+m(10+1)$ $\Rightarrow$$T=2.75\,N$ Hence, the correction option is [b].