Two particles A and B, having same mass m are tied to a common point of suspension O. A is tied with the help of an inextensible string of length L and B is tied using an elastic string of unstretched length `(L)/(2)` . The two particles are released from horizontal positions as shown in figure. The particles have been released at a time gap so that both the string and the elastic cord become vertical simultaneously. It was observed that the length of the cord became equal to that of the string at this moment and the two particles collided. The particles got stuck together and their velocity just after the collision was observed to be `(sqrt(gL))/(2)`.

(a) In which direction will the combined mass move immediately after collision – right or left ?
(b) Find tension in the string immediately after the collision.

Answer

(a) Left
(b) Zero