$A$ body of mass $2 \ kg$ moving with a velocity of $6 \ m/s$ strikes inelastically another body of same mass at rest. The amount of heat evolved during collision is ............... $J$.

$A$ ball is dropped from a height of $10 \,m$. The ball embeds itself $1 \,m$ into the sand and stops. Which of the following statements is correct regarding this process?

$A$ 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 .............. $J$.

$A$ body of mass $1 \ g$ moving with a velocity of $3\hat{i} - 2\hat{j} \ m/s$ collides with a body of mass $2 \ g$ moving with a velocity of $4\hat{j} - 6\hat{k} \ m/s$. If the two bodies stick together after the collision,what is the magnitude of their combined velocity in $m/s$?

Two cars of equal mass $m$ moving with the same speed $v$ undergo a perfectly inelastic collision. What is the velocity of the combined mass after the collision?

$A$ 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 ............. $J$.