A water pump takes water through 12m. Water is discharged at the surface at the rate of 2Kg/s, and the discharge speed of each drop is 3m/s. Find the minimum power of the pump

Alead ball is dropped into a lake from a diving board 5m above the water . it hits the water with a certain velocity and then sink with constant velocity in bottom . it reaches the bottom 5 second after it is dropped if g= 10m/s2 . find depth of the lake and average velocity of the ball ?