In the pulley-block system shown in figure strings are light, the pulleys are light and smooth. The system is released from rest. At t = 0.3 s

Using the concepts of Laws of Motion and Kinematics we can draw following diagrams and then using the definition of work, we can find Corresponding work done.

$$\begin{gathered} For 1 kg body 2T-10=2\frac{a}{2} \\ for 2 kg body 20-T=2a \\ solving the two equation we get T=\frac{20}{3}N \end{gathered}$$