$A$ body of mass $4\, kg$ moving with velocity $12\, m/s$ collides with another body of mass $6\, kg$ at rest. If two bodies stick together after collision,then the loss of kinetic energy of the system is .............. $J$.

$A$ mass of $20\, kg$ moving with a speed of $10\, m/s$ collides with another stationary mass of $5\, kg$. As a result of the collision,the two masses stick together. The kinetic energy of the composite mass will be ............. $J$.

$A$ bullet of mass $m$ travelling with a speed $v$ hits a block of mass $M$ initially at rest and gets embedded in it. The combined system is free to move and there is no other force acting on the system. The heat generated in the process will be

$A$ particle of mass $m$ moving towards west with speed $v$ collides with another particle of mass $m$ moving towards south. If the two particles stick to each other,the speed of the new particle of mass $2m$ will be ..........

$A$ body of mass $2\, kg$ moving with a velocity of $3\, m/s$ collides head-on with a body of mass $1\, kg$ moving in the opposite direction with a velocity of $4\, m/s$. After the collision,the two bodies stick together and move with a common velocity. The common velocity in $m/s$ is equal to:

$A$ scooter of $40\,kg$ mass moving with velocity $4\,m/s$ collides with another scooter of $60\,kg$ mass moving with velocity $2\,m/s$ in the same direction. After the collision,the two scooters stick to each other. The loss in kinetic energy is .............. $J$.