Touching a hemispherical dome of radius `R` there is a vertical tower of height `H = 4 r`
Channel: Doubtnut
Date: 2020-04-05

Touching a hemispherical dome of radius `R` there is a vertical tower of height `H = 4 r`. A boy projects a ball horizontally at speed `u` from the top of the tower. The ball strikes the dome at a height `(R)/(2)` from ground and rebounds. After rebounding the ball retraces back its path into the hands of the boy. Then the value of `u` is : img src="https://d10lpgp6xz60nq.cloudfront.net/physics_images/RES_P07_17_APCT_P7_XI_E01_003_Q01.png" width="80%"