Two blocks are in contact on a frictionless table. One has mass $m$ and the other $2\,m$. A force $F$ is applied on $2\,m$ as shown in the figure. Now the same force $F$ is applied from the right on $m$. In the two cases respectively, the ratio force of contact between the two block will be:

A body of mass $1\, kg$ lies on smooth inclined plane. The body is given force $F = 10N$  horizontally as shown. The magnitude of net normal reaction on the body is 

Two blocks of mass $M_1 = 20\,kg$ and $M_2 = 12\,kg$ are connected by a metal rod of mass $8\,kg.$ The system is pulled vertically up by applying a force of $480\,N$ as shown. The tension at the mid-point of the rod is ........ $N$

A uniform rope of mass $1.0\, kg$ is connected with a box of mass $2.0\, kg$, which is placed on a smooth horizontal surface. The free end of the rope is pulled horizontally by a force $6\, N$. Find the tension at the midpoint of the rope ....... $N$

Four blocks are connected as shown in the fig. on a horizontal frictionless surface of $m_1 = m_2 = m_3 = m_4$ then $T_3/T_4$ will be

Two particle of mass $m$ each are tied at the ends of a light string of length $2 \mathrm{a}$. The whole system is kept on a frictionless horizontal surface with the string held tight so that each mass is at a distance $'a'$ from the center $\mathrm{P}$ (as shown in the figure). Now, the mid-point of the string is pulled vertically upwards with a small but constant force $F$. As a result, the particles move towards each other on the surface. The magnitude of acceleration, when the separation between them becomes $2 \mathrm{x}$ is