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

Two identical blocks of ice move in opposite directions with equal speed and collide with each other. What will be the minimum speed required to make both the blocks melt completely,if the initial temperatures of the blocks were $-8^{\circ} C$ each (in $ms^{-1}$)? (Specific heat of ice is $2100 \ Jkg^{-1} K^{-1}$ and latent heat of fusion of ice is $3.36 \times 10^{5} \ Jkg^{-1}$)

$A$ particle of mass $m$ moving with velocity $v$ collides with a stationary particle of mass $2m$ and sticks to it. What will be the speed of the system?

$A$ body of mass $40 \ kg$ moves with a velocity of $4 \ m/s$,and another body of mass $60 \ kg$ moves with a velocity of $2 \ m/s$. If they undergo a perfectly inelastic collision,the loss in kinetic energy is $... \ J$.

$A$ particle of mass $m$ moving eastward with a speed $v$ collides with another particle of the same mass moving northwards with the same speed $v$. The two particles coalesce on collision. The new particle of mass $2m$ will move with velocity:

$A$ body of mass $40\,kg$ having velocity $4\,m/s$ collides with another body of mass $60\,kg$ having velocity $2\,m/s$. If the collision is perfectly inelastic, then the loss in kinetic energy will be .............. $J$.