Explanation:
Velocity : Velocity is quickness of motion or action. A synonym is celerity; a simpler word is speed. In physics, velocity specifically refers to the measurement of the rate and direction of change in position of an object. It is a vector quantity that specifies both the speed of a body and its direction of motion.
Power : In physics, power is the amount of energy transferred or converted per unit time. In the International System of Units, the unit of power is the watt, equal to one joule per second. In older works, power is sometimes called activity. Power is a scalar quantity.
Hope it's helpful to you
In order to know how long it has been falling for you take the final velocity "49m/s" and divide it by the acceleration "9.8m/s" and get 5, since you have been using seconds in the calculations the answer is 5 seconds. (Fun fact, it is actually 9.82m/s per second since it accelerates and they rounded it down.)
