Three masses of $16, 8$ and $4\,kg$ are placed in contact as shown in figure. If a force of $140\,N$ is applied on $4\,kg$ mass, then the force on $16\,kg$ will be  ............ $ N$

Two block of masses $7\, kg$ and $5\, kg$ are placed in contact with each other on a smooth surface. If a force of $6\, N$ is applied on the heavier mass, the force on the lighter mass is ............ $N$

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 ........ $N$

The tension in the string which connected the blocks as shown in the following figure  ............ $ N$

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

A book of mass $5 \,kg$ is placed on a table and it is pressed by $10 \,N$ force then normal force exerted by the table on the book is ......... $N$