In the figure given below,what is the reading of the spring balance (in $, N$)? (Take $g = 10\, N \,kg^{-1}$)

If $m_1 = 4m_2$,and the acceleration of $m_1$ is $a$,then find $a$.

$A$ man uses two pulleys to raise himself with an acceleration of $2\,m/s^2$,as shown in the figure. The man stands on a light weighing machine fitted on a horizontal platform. Determine the reading of the weighing machine. (Mass of man $= 75\,kg$,mass of platform $= 25\,kg$,$g = 10\,m/s^2$) (in $,N$)

For the system shown in the figure,$m_1 > m_2 > m_3 > m_4$. Initially,the system is at rest in equilibrium. If the string joining $m_4$ and the ground is cut,then just after the string is cut:
Statement $I$: $m_1$,$m_2$,and $m_3$ remain stationary.
Statement $II$: The value of acceleration of all the $4$ blocks can be determined.
Statement $III$: Only $m_4$ remains stationary.
Statement $IV$: Only $m_4$ accelerates.
Statement $V$: All the four blocks remain stationary.
Now,choose the correct option.

Three blocks of masses $m_1=4 \, kg$, $m_2=2 \, kg$, and $m_3=4 \, kg$ are connected with ideal strings passing over a smooth, massless pulley as shown in the figure. The acceleration of the blocks will be ......... $m/s^2$ $(g=10 \, m/s^2)$.

Two masses $m_1 = 5\, kg$ and $m_2 = 4.8\, kg$ tied to a string are hanging over a light frictionless pulley. The acceleration of the masses when they are free to move is $...........\, m/s^2$. $(g = 9.8\, m/s^2)$