$A$ body of mass $1000 \text{ kg}$ is moving horizontally with a velocity of $6 \text{ m/s}$. If an extra mass of $200 \text{ kg}$ is added to it,what will be the final velocity (in $\text{m/s}$)?

Two balls in free space are colliding with each other. Which of the following statements regarding linear momentum conservation of the system is true?

$A$ person of mass $M=90 \ kg$ standing on a smooth horizontal plane of ice throws a body of mass $m=10 \ kg$ horizontally on the same surface. If the distance between the person and the body after $10 \ s$ is $10 \ m$,then the kinetic energy $(KE)$ of the person (in $J$) is: (in $J$)

An open water-tight railway wagon of mass $5 \times 10^3 \text{ kg}$ coasts at an initial velocity $1.2 \text{ m/s}$ without friction on a railway track. Rain drops fall vertically downwards into the wagon. The velocity of the wagon after it has collected $10^3 \text{ kg}$ of water will be .............. $\text{m/s}$.

An isolated rail car of mass $M$ is moving along a straight,frictionless track at an initial speed $v_0$. The car is passing under a bridge when a crate filled with $N$ bowling balls,each of mass $m$,is dropped from the bridge into the bed of the rail car. The crate splits open and the bowling balls bounce around inside the rail car,but none of them fall out. What is the average speed of the rail car $+$ bowling balls system some time after the collision?

You are on a frictionless horizontal plane. How can you get off if no horizontal force is exerted by pushing against the surface?