A bomb of mass $9 \,kg$ explodes into two pieces of masses $3 \,kg$ and $6 \,kg$. The velocity of mass $3 \,kg$ is $16 \,m / s$. The kinetic energy of mass $6 \,kg$ in joule is

A bullet of mass $40 \,g$ is fired from a gun of mass $10 \,kg$. If velocity of bullet is $400 \,m / s$, then the recoil velocity of the gun will be ..........

If final momentum is equal to initial momentum of the system then

Rocket engines lift a rocket from the earth surface because hot gas with high velocity

Two spheres $A$ and $B$ of masses $m_1$ and $m_2$ respectively collide. $A$ is at rest initially and $B$ is moving with velocity $v$ along $x-$ axis. After collision $B$  has a $\frac {v}{2}$ velocity in a direction perpendicular to the original direction. The mass $A$ moves after collision in the direction

A cannon ball is fired with a velocity $200\, m/sec$ at an angle of $60° $ with the horizontal. At the highest point of its flight it explodes into $3$ equal fragments, one going vertically upwards with a velocity $100 \,m/sec$, the second one falling vertically downwards with a velocity $100\, m/sec$. The third fragment will be moving with a velocity