What Physical science is happening between me and my GF? or is there any?

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 ?

If the ama of the inclined plane below is 2, calculate the ima and efficiency. ima = efficiency =

What is the measure of a change in an objects velocity?