If we ignore air friction, both balls will hit the ground at the same time, regardless of their masses or initial velocities (assuming the heights from which they are thrown are the same). This observation is based on the principle of Galileo's free-fall experiment, which states that in the absence of air resistance, all objects near the Earth's surface will fall with the same acceleration, known as the acceleration due to gravity (denoted as "g").
The acceleration due to gravity is approximately constant near the surface of the Earth, and it is equal to about 9.8 meters per second squared (m/s²). Therefore, regardless of their masses or initial velocities, both balls will experience the same acceleration due to gravity as they fall. As a result, they will reach the ground simultaneously. This assumes no other factors such as external forces or significant differences in shape or size between the two balls.