$A$ dynamometer $D$ is attached to two blocks of masses $6 \, kg$ and $4 \, kg$ as shown in the figure. The reading of the dynamometer is ............ $N$.

$A$ rope of mass $5 \,kg$ is moving vertically in a vertical position with an upward force of $100 \,N$ acting at the upper end and a downward force of $70 \,N$ acting at the lower end. The tension at the midpoint of the rope is ......... $N$.

Three solids of masses $m_1, m_2$ and $m_3$ are connected with weightless strings in succession and are placed on a frictionless table. If the mass $m_3$ is dragged with a force $T$,the tension in the string between $m_2$ and $m_3$ 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 $\left( \frac{\text{Tension in the string between } P \text{ and } Q}{\text{Tension in the string between } O \text{ and } P} \right)?$

Three identical particles are joined together by a thread as shown in the figure. All the three particles are moving on a smooth horizontal plane about point $O$. If the speed of the outermost particle is $v_0$,then the ratio of tension in the three sections of the thread is:

Two blocks $A$ and $B$,each of mass $m$,are placed on a smooth horizontal surface. Two horizontal forces $F$ and $2F$ are applied on the two blocks $A$ and $B$ respectively,as shown in the figure. The block $A$ does not slide on block $B$. Then,the normal reaction acting between the two blocks is