A balloon is rising up along the axis of a concave mirror of radius of curvature`20m`A ball is
Channel: Doubtnut
Date: 2020-08-23

A balloon is rising up along the axis of a concave mirror of radius of curvature`20m`A ball is dropped from the balloon at  a height `15m`from the mirror when the balloob has velocity `20m//s`.Find the speed of the image of the ball formed by concave mirror after`4`seconds[take:`g=10m//s^(2)`]