What is velocity usually expressed in

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 ?

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When a lead acid car battery is recharged by the alternator, it acts essentially as an electrolytic cell in which solid lead(ii) sulfate is reduced to lead at the cathode and oxidized to solid lead(ii) oxide at the anode. suppose a current of is fed into a car battery for seconds. calculate the mass of lead deposited on the cathode of the battery.