Six identical marbles are lined up in a straight groove made on a horizontal frictionless surface as shown in figure. Two similar marbles each moving with a velocity $v$  collide with the row of 6 marbles from the left. What is observed?

 

 

All eight marbles will start moving to the right, each with speed of  $v/8$

All six marbles in the row will roll out with a speed $v/6$  each, the two incident marbles will come to rest

One marble from the right rolls out with a speed $2v,$  the remaining marbles do not move

Two marbles from the right rollout with a speed  $v$ each, the remaining marbles do not move