A small steel ball bounces on a steel plate held horizontally. On each bounce the speed of the ball arriving at the plate is reduced by a factor e (coefficient of restitution) in the rebound , so that V_("upward")=eV_("downward") If the ball is initially dropped from a height of 0.4m above the plate and if 10s later the bouncing ceases, the value of e is

A small steel ball bounces on a steel plate held horizontally. On each

1.	A small steel ball bounces on a steel plate held horizontally. On each bounce the speed of the ball arriving at the plate is reduced by a factor e (coefficient of restitution) in the rebound , so that V_("upward")=eV_("downward") If the ball is initially dropped from a height of 0.4m above the plate and if 10s later the bouncing ceases, the value of e is
Answer» `sqrt(2/7)` `3/4` `(13)/(18)` `(17)/(18)` Solution :We know, `t=sqrt((2h)/g)[(1+E)/(1-e)]` `THEREFORE 10=sqrt((2xx0.4)/(10))[(1+e)/(1-e)] ["taking" g=10m//s^2]` `or, e=(25sqrt(2)-1)/(25sqrt(2)+1)~~(17)/(18)`