Question

The Fig. showns a string of equally placed beads of mass m, separated by distance. The beads are free to slide without friction on a thin wire. A constant force F act on the first bead initially at rest till it makes collision with the second bead. The second bead then collides with the third and so on. Supposed that all collisions are elastic,

A. Speed of the first immediately before and immediately after its collision with the second bead is `sqrt((2Fd)/(m))` and zero respectively
B. Speed of the first bead immediately before and immediately after its collision with the second bead is `sqrt((2Fd)/(m))` and `(1)/(2) sqrt((2Fd)/(m))` respectively
C. Speed of the second bead immediately after collision with third bead is zero
D. The average speed of the first bead is `(1)/(2)sqrt(2Fd)/(m)`

Answer 1

Correct Answer - A::C
In elastic head on collision if the masses of the collision bodies are eaqual, the velocities after for `Ist` bead, `Fd = (1)/(2) m u^(2) rArr u = sqrt((2Fd)/(m))`