$A$ bullet of mass $m$ is fired horizontally with a velocity $u$ into a sandbag placed on a truck. If the mass of the truck is $M$, what will be the velocity of the truck after the collision?

$A$ bag of mass $M$ is suspended by a string. $A$ bullet of mass $m$ moving with velocity $v$ enters the bag and gets embedded in it. Then,for the system:

$A$ particle of mass $m$ moving eastward with a speed $v$ collides with another particle of the same mass moving northward with the same speed $v$. The two particles coalesce on collision. The new particle of mass $2m$ will move in the north-easterly direction with a velocity

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

$A$ scooter of mass $40 \ kg$ moving with a velocity of $4 \ m/s$ collides with another scooter of mass $60 \ kg$ moving with a velocity of $2 \ m/s$. After the collision,both scooters stick together. Find the loss in kinetic energy in $J$.

$A$ 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: