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 ............ $N$

A horizontal force $10 \mathrm{~N}$ is applied to a block $A$ as shown in figure. The mass of blocks $A$ and $B$ are $2 \mathrm{~kg}$ and $3 \mathrm{~kg}$ respectively. The blocks slide over a frictionless surface. The force exerted by block $A$ on block $B$ is :

Figure shows three blocks in contact and kept on a smooth horizontal surface. What is ratio of force exerted by block $A$ on $B$ to that of $B$ on $C$

Three blocks of masses $4\, kg, 8\,kg$ and $24 \,kg$ are connected to each other with  light strings and placed on a smooth horizontal floor as shown in figure. If the system  moves with an acceleration of $2\, ms^{-2}$, the applied force $F$ is ............ $N$

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$

A block '$A$' takes $2\,s$ to slide down a frictionless incline of $30^{\circ}$ and length ' $l$ ', kept inside a lift going up with uniform velocity ' $v$ '. If the incline is changed to $45^{\circ}$, the time taken by the block, to slide down the incline, will be approximately $........\,s$