A shell at rest at the origin explodes into three fragments of masses $1\ kg$ , $2\ kg$ and $m\ kg$ . The $1\ kg$ and $2\ kg$ pieces fly off with speeds of $5\ ms^{-1}$ along $x-axis$ and $6\ ms^{-1}$ along $y-axis$ respectively. If the $m\, kg$ piece flies off with a speed of $6.5\ ms^{-1}$ , the total mass of the shell must be    ……… $kg$

An initially stationary device lying on a frictionless floor explodes into two pieces and slides across the floor one piece is moving in positive $x$ direction then other peice is moving in

A shell of mass $0.020\; kg$ is fired by a gun of mass $100\; kg$. If the muzzle speed of the shell is $80 \;m s^{-1}$, what is the recoil speed in $m/s$ of the gun ?

A man fires a bullet of mass $200 \,g$ at a speed of $5 \,m/s$. The gun is of one $kg$ mass. by what velocity the gun rebounds backwards …….. $m/s$

A shell, in flight, explodes into four unequal parts. Which of the following is conserved?