$A$ moving block having mass $m$ collides with another stationary block having mass $4m$. The lighter block comes to rest after the collision. If the initial velocity of the lighter block is $v$,then the value of the coefficient of restitution $(e)$ will be:

If a body collides inelastically with another body of the same mass initially at rest,what will be the ratio of their speeds after the collision?

$A$ ball with a speed of $9\, m/s$ collides with another identical ball at rest. After the collision,the direction of each ball makes an angle of $30^{\circ}$ with the original direction. The ratio of velocities of the balls after collision is $x : y$ where $x$ is........

$A$ ball moving with a velocity of $9 \ m/s$ collides with another similar stationary ball. After the collision,both balls move in directions making an angle of $30^{\circ}$ with the initial direction. After the collision,their speed will be $-$

$A$ sphere collides with another sphere of identical mass. After collision,the two spheres move. The collision is inelastic. Then the angle between the directions of the two spheres is

$A$ sphere of mass $m$ moving with velocity $v$ collides head-on with another sphere of the same mass which is at rest. The ratio of the final velocity of the second sphere to the initial velocity of the first sphere is (where $e$ is the coefficient of restitution and the collision is inelastic).