Four blocks are connected as shown in the figure on a horizontal frictionless surface. If $m_1 = m_2 = m_3 = m_4 = m$,then the ratio $T_3 / T_4$ will be:

$A$ block of mass $4 \,kg$ is suspended through two light spring balances $A$ and $B$ as shown in the figure. Then $A$ and $B$ will read respectively:

$A$ block of mass $M$ is kept on a platform which starts accelerating upwards from rest with a constant acceleration $a$. During the time interval $T$,the work done by the contact force on mass $M$ is

Two blocks of $2 \,kg$ and $1 \,kg$ are in contact on a frictionless table. If a force of $3 \,N$ is applied on the $2 \,kg$ block, then the force of contact between the two blocks will be: (in $\,N$)

$A$ block of mass $18.5 \ kg$ kept on a smooth horizontal surface is pulled by a rope of $3 \ m$ length by a horizontal force of $40 \ N$ applied to the other end of the rope. If the linear density of the rope is $0.5 \ kg \ m^{-1}$ and initially the block is at rest,the time in which the block moves a distance of $9 \ m$ is: (in $s$)

The figure shows a boy on a horizontal platform $A$ on a smooth horizontal surface,holding a rope attached to a box $B$. The boy pulls the rope with a constant force of $50 \ N$. (The boy does not slip over the platform). The combined mass of platform $A$ and the boy is $250 \ kg$,and that of box $B$ is $500 \ kg$. The velocity of $A$ relative to the box $B$,$5 \ s$ after the boy on $A$ begins to pull the rope,will be ............ $m/s$.