A perfect smooth sphere $A$ of mass $2 \mathrm{kg}$ is in contact with a rectangular block $B$ of mass $4 \mathrm{kg}$ and vertical wall as shown in the figure. All surfaces are smooth. Find normal reaction by vertical wall on sphere $A$.

A flexible chain of weight $W$ hangs between two fixed points $A$ and $B$ at the same level. The inclination of the chain with the horizontal at the two points of support is $\theta .$ What is the tension of the chain at the two segments

A cylinder rests in a supporting carriage as shown. The side $AB$ of carriage makes an angle $30°$ with the horizontal and side $BC$ is vertical. The carriage lies on a fixed horizontal surface and is being pulled towards left with a horizontal acceleration $a$. The magnitude of normal reactions exerted by sides $AB$ and $BC$ of carriage on the cylinder are $N_{\mathrm{AB}}$ and $N_{\mathrm{BC}}$, respectively. Neglect friction everywhere. Then, as the magnitude of acceleration $a$ of the carriage is increased, pick up the correct statement.

Two blocks $A$ and $B$ of masses $10 \mathrm{kg}$ and $40 \mathrm{kg}$ are connected by an ideal string as shown in the figure. Neglect the masses of the pulleys and effect of friction $\left(g=10 \mathrm{m} {\mathrm{s}}^{-2}\right)$.

Two blocks $A$ and $B$ of masses $m \& 2m$, respectively are held at rest such that the spring is in natural length. Find out the accelerations of blocks $A$ and $B$, respectively just after release (pulley, string and spring are massless).

System shown in figure is in equilibrium. The magnitude of change in tension in the string just before and just after, when one of the spring is cut. Mass of both the blocks is same and equal to $m$ and spring constant of both springs is $k.$ (Neglect any effect of rotation)

Assertion: Block $A$ is moving on horizontal surface towards right under action of force $F$. All surfaces are smooth. At the instant shown, the force exerted by block $A$ on block $B$ is equal to net force on block $B$. 

Reason: From Newton's third law, the force exerted by block $A$ on $B$ is equal in magnitude to force exerted by block $B$ on $A$.

Assertion: A man standing in a lift which is moving upward will feel his weight to be greater than when the lift was at rest.

Reason: If the acceleration of the lift is $a$ upwards, then the man of mass $m$ shall feel his weight to be equal to normal reaction $\left(N\right)$ exerted by the lift given by, $N=m(g+a)$ (where, $g$ is acceleration due to gravity).