A train has $10$ wagons each of mass $1000 \mathrm{kg}$ attached to it. They are being pulled by force ${10}^4 \mathrm{N}$. Find out the force exerted on the last four wagons.
                                                                         

If $m_1=m_2=1 \mathrm{kg}$ then find out the distance travelled by $m_1$ in the first $\frac{1}{2}$ second. 

Two blocks $A$ and $B$ of masses $3m$ and $m$ respectively are connected by a massless and inextensible string. The whole system is suspended by a massless spring as shown in the figure. The magnitudes of acceleration of $A$ and $B$ immediately after the string is cut, are respectively:-

Force of $3 \mathrm{N}$ acts on a system of two blocks of mass $2 \mathrm{kg}$ and $1 \mathrm{kg}$ as shown in the figure. The contact force between the blocks is:
 

If the string is pulled with the acceleration of $2 \mathrm{m} {\mathrm{s}}^{-2}$, then the acceleration of the block is

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