In the diagram shown, the normal reaction force between $2\,kg$ and $1\,kg$ is (Consider the surface, to be smooth)$.........N$ (Given $g =10\,ms ^{-2}$)

Three blocks $A, B$ and $C$ of masses $4\, kg$, $2\, kg$ and $1\, kg$ respectively, are in contact on a frictionless surface, as shown. If a force of $14\, N$ is applied on the $4\, kg$ block, then the contact force between $A$ and $B$ is .......... $N$

A block of mass $M$ is at rest on a plane surface inclined at an angle $\theta$ to the horizontal. The magnitude of force exerted by the plane on the block is

What force should be applied on the wedge so that block over it does not move? (All surfaces are smooth)

Three blocks $A, B$ and $C $ weighing $1, 8$ and $27\, kg$ respectively are connected as shown in the figure with an inextensible string and are moving on a smooth surface. ${T_3}$ is equal to $36\, N$. Then ${T_2}$ is ........ $N$

$T_1$ and $T_2$ in the given figure are