Two blocks $A$ and $B$, each of mass $20 \,kg$, lying on a frictionless table, are connected by a light string. The system is pulled horizontally with an acceleration of $2 \,ms^{-2}$ by a force $F$ applied on block $B$. The tension in the string will be: (in $\,N$)

Two unequal masses are connected on two sides of a light string passing over a light and smooth pulley as shown in the figure. The system is released from rest. The larger mass $(2\, kg)$ is stopped $1\, s$ after the system is set into motion and then released. Find the time elapsed before the string becomes tight again. (Take $g = 10\, m/s^2$)

$A$ mass of $10 \; kg$ is suspended by a rope of length $4 \; m$ from the ceiling. $A$ force $F$ is applied horizontally at the mid-point of the rope such that the top half of the rope makes an angle of $45^{\circ}$ with the vertical. Then $F$ equals ........... $N$ (Take $g = 10 \; ms^{-2}$ and the rope to be massless).

Two bodies of mass $4\,kg$ and $6\,kg$ are attached to the ends of a string passing over a pulley. The $4\,kg$ mass is also attached to the ground by another string. The tension $T_1$ in this lower string is equal to ......... $N$ (Take $g = 9.8\,m/s^2$)

$A$ block of mass $1\,kg$ is suspended by a string of mass $1\,kg$ and length $1\,m$ as shown in the figure. $(g = 10\,m/s^2)$. Calculate the tension (in $N$) in the string at its lowest point.

$A$ uniform chain of length $2L$ is hanging in an equilibrium position. If end $B$ is given a slightly downward displacement,the imbalance causes an acceleration. Here,the pulley is small and smooth,and the string is inextensible. Find the velocity $v$ of the chain when it slips out of the pulley (height of pulley from floor $> 2L$).