How has the theory of the Universe changed over time? The idea changed from Earth-centered to Sun-centered over time.

The idea changed from Sun-centered to Earth-centered over time.

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be

snell's law

refractve index = sin incidence / sin refraction

1 is a answer of a question