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 ......... $m/s^2$ $(g=10 \, m/s^2)$.

To paint the side of a building,a painter normally hoists himself up by pulling on the rope $A$ as shown in the figure. The painter and platform together weigh $200 \, N$. The rope $B$ can withstand a maximum tension of $300 \, N$. Then:

$A$ block of mass $25 \; kg$ is raised by a $50 \; kg$ man in two different ways as shown in the figure. What is the action on the floor by the man in the two cases? If the floor yields to a normal force of $700 \; N$,which mode should the man adopt to lift the block without the floor yielding?

In the figure, the tension in the diagonal string is $60\,N$. Find the magnitude of the horizontal forces $F_1$ and $F_3$ that must be applied to hold the system in the position shown.

$A$ 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 $,N$)

$A$ pendulum bob of mass $50 \,g$ is suspended from the ceiling of an elevator. The tension in the string if the elevator goes up with uniform velocity is approximately .......... $N$.