$A$ block of mass $m$ is kept on a platform which starts from rest with constant acceleration $g/2$ upward,as shown in the figure. Work done by the normal reaction on the block in time $t$ is

For the given figure,find the value of $m$ (in $kg$) for which the blocks have an acceleration of $\frac{8}{13}g$. The block on the incline has a mass of $100 \, g = 0.1 \, kg$ and the hanging block on the left has a mass of $50 \, g = 0.05 \, kg$. The surface is frictionless $(\mu = 0)$.

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

$A$ mass $1\, kg$ is suspended by a thread. It is
$(i)$ lifted up with an acceleration $4.9\, m/s^2$
$(ii)$ lowered with an acceleration $4.9\, m/s^2$.
The ratio of the tensions is

On a smooth plane surface,two blocks $A$ and $B$ are accelerated by applying a force of $15 \, N$ on block $A$. If the mass of block $B$ is twice that of block $A$,the force on block $B$ is ........... $N$.

Three blocks of masses $3\, kg, 2\, kg$,and $1\, kg$ are placed side by side on a smooth surface as shown in the figure. $A$ horizontal force of $12\, N$ is applied to the $3\, kg$ block. The net force on the $2\, kg$ block is ............ $N$.