$250 \; N$ force is required to raise a $75 \; kg$ mass using a pulley system. If the rope is pulled by $12 \; m$ and the load is lifted by $3 \; m$,the efficiency of the pulley system will be ......$\%$

$A$ lift is tied with thick iron ropes having mass $M$. The maximum acceleration of the lift is $a \ m/s^2$ and the maximum safe stress is $S \ N/m^2$. The minimum diameter of the rope is

$A$ body of weight $200 \,N$ is suspended from a tree branch through a chain of mass $10 \,kg$. The branch pulls the chain by a force equal to (if $g=10 \,m/s^2$): (in $\,N$)

If the mass of block $B$ is $3\,kg$ and the mass of block $A$ is $7\,kg$,then the acceleration of the system is ........... $m/s^2$. $(g = 10\,m/s^2)$

The same spring is attached to $2 \ kg, 3 \ kg$ and $1 \ kg$ blocks in three different cases as shown in the figure. If $x_1, x_2$ and $x_3$ are the extensions in the spring in these cases,respectively,find the correct relation between them.

Three blocks $M_1, M_2, M_3$ having masses $4 \ kg, 6 \ kg$ and $10 \ kg$ respectively are hanging from a smooth pulley using ropes $1, 2$ and $3$ as shown in the figure. The tension in the rope $1, T_1$,when they are moving upward with an acceleration of $2 \ m/s^2$ is ............... $N$ (if $g = 10 \ m/s^2$).