A 300g ball and a 100g ball are dropped from a tower. Both balls are the same size and their is no air resistance. Which one hits the ground first?

Answer: The balls would hit the ground at the same time.

Explanation: Since there is no air resistance, we would put Galileo's experiment into motion. Galileo once performed an experiment of dropping two items, with different masses, from the tower of Pisa. Since there was no air resistance, the balls hit the ground at the same time. In this problem, the balls are "free-falling." Freefall is a term used in Physics to describe the motion of a falling object experiencing only the acceleration due to gravity. g=9.8 m/s^2 (acceleration due to gravity.) 9.8 will always be the acceleration in a free fall event like this with no air resistance, since Gravity remains constant.

Newton's second law of motion states that F=ma, (force is equal to mass times acceleration), but since Newton also states that f=mg, we can conclude that ma=mg. Stating that no matter what the mass of the object is, both of the objects will fall at the same time with the same velocity.