$T_1$ and $T_2$ in the given figure are

If a ship of mass $4 \times 10^{7} \,kg$ initially at rest is pulled by a force of $5 \times 10^{4} \,N$ through a distance of $4 \,m$, then the speed of the ship will be (resistance due to water is negligible). (in $\,ms^{-1}$)

Consider two masses $m_1$ and $m_2$ connected through a pulley as shown in the figure. Mass $m_2$ starts from rest at height $h$ and falls down. With what speed does it hit the ground? (Assume no friction and massless strings and pulleys.)

Three blocks of masses $m_1, m_2$ and $m_3$ are connected by massless strings as shown on a frictionless table. They are pulled with a force $F = 40 \, N$. If $m_1 = 10 \, kg, m_2 = 6 \, kg$ and $m_3 = 4 \, kg$,the tension $T_2$ (between $m_1$ and $m_2$) will be ........ $N$.

Three blocks are connected as shown in the figure on a horizontal frictionless table. If $m_1 = 1 \, kg, m_2 = 8 \, kg, m_3 = 27 \, kg$ and $T_3 = 36 \, N$,then $T_2$ will be ............ $N$.

Two blocks $A$ and $B$ of mass $m$ and $2m$ respectively are connected by a massless spring of force constant $k$. They are placed on a smooth horizontal plane. The spring is stretched by an amount $x$ and then released. The relative velocity of the blocks when the spring comes to its natural length is: