pastor a balloon of mass 0.030 kg being inflated with a gas of density 0.54 kg metre raise to power - 3 what will be the volume of the balloon when it begins to rise in a of density 1.29 kg metre is power - 3g= 10 m/s2​

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 ?