The maximum tension a rope can withstand is $60 \,kg$-wt. The ratio of maximum acceleration with which two boys of masses $20 \,kg$ and $30 \,kg$ can climb up the rope at the same time is

Two spheres $P$ and $Q$ of equal masses $m$ are attached to a string of total length $2\, m$ as shown in the figure. The string and the spheres are then whirled in a horizontal circle about $O$ at a constant angular velocity $\omega$. The distance $OP = 1\, m$ and $PQ = 1\, m$. What is the value of the ratio $\left( \frac{\text{Tension in the string between } P \text{ and } Q}{\text{Tension in the string between } O \text{ and } P} \right)?$

Two blocks of masses $2m$ and $m$ are placed on a smooth horizontal surface. $A$ force $F$ is applied on the $2m$ block towards the right,and the same force $F$ is applied on the $m$ block towards the left. What is the ratio of the contact forces between the two blocks in the two cases?

$A$ block of mass $1 \, kg$ is suspended by a string of mass $1 \, kg$ and length $1 \, m$ as shown in the figure. Taking $g = 10 \, m/s^2$,calculate the force exerted by the support on the string. (in $, N$)

$A$ block of mass $m_1$ rests on a horizontal table. $A$ string tied to the block is passed over a frictionless pulley fixed at the end of the table,and to the other end of the string is hung another block of mass $m_2$. The acceleration of the system is

An elevator accelerates upwards at a constant rate. $A$ uniform string of length $L$ and mass $m$ supports a small block of mass $M$ that hangs from the ceiling of the elevator. The tension at distance $l$ from the ceiling is $T$. The acceleration of the elevator is