For the given figure what will be the contact force applied by $6\ kg$ block on $4\ kg$ block ............ $N$

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

A block $B$ is placed on block $A$. The mass of block $B$ is less than the mass of block $A$. Friction exists between the blocks, whereas the ground on which the block $A$ is placed is taken to be smooth. $A$ horizontal force $F$, increasing linearly with time begins to act on $B$. The acceleration ${a_A}$ and ${a_B}$ of blocks $A$ and $B$ respectively are plotted against $t$. The correctly plotted graph is

Two bodies of masses $m_{1}=5\,kg$ and $m _{2}=3\,kg$ are connected by a light string going over a smooth light pulley on a smooth inclined plane as shown in the figure. The system is at rest. The force exerted by the inclined plane on the body of mass $m _{1}$ will be$....N$ [Take $g=10\,ms ^{-2}$ ]

A monkey is decending from the branch of a tree with constant acceleration. If the breaking strength is $75 \%$ of the weight of the monkey, the minimum acceleration with which monkey can slide down without breaking the branch

A block of mass $m$ is placed on a smooth inclined wedge $ABC$ of  inclination $\theta$ as shown in the figure. The wedge is given an acceleration $a$ towards the right. The relation between $a$ and $\theta$ for the block to remain stationary on the wedge is