Does every scientific method begin with an observation? explajn.

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 ?

What is the average speed of a car that travels 40 mph for 1 hour and 60 mph in another hour?

Petroleum contains energy. a. light b. kinetic c. chemical d. mechanical