Help me please.. Speed is?

A) A measure of how fast something is moving

B) The distance covered per unit time

C) Always measured in terms of distance divided by time

D) All of the above

E) None of the above

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 ?

Why do astronauts in the space shuttle weigh less?

How can waves travel through ground?