The reason objects of different masses fall to the ground at the same time, neglecting air resistance, is due to the acceleration due to gravity being the same for all objects near the surface of the Earth. This concept is often referred to as the "equivalence principle" or "Galilean equivalence."
According to Isaac Newton's law of universal gravitation, the force of gravity acting on an object is proportional to its mass. Mathematically, this is expressed as F = m * g, where F is the force of gravity, m is the mass of the object, and g is the acceleration due to gravity.
Now, according to Newton's second law of motion, the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. Mathematically, this is expressed as a = F / m.
Combining these two equations, we find that the acceleration due to gravity, denoted as "g," is independent of the mass of the object. This means that all objects, regardless of their mass, experience the same acceleration when they fall near the surface of the Earth.
As a result, if we neglect other factors such as air resistance, the time it takes for objects to fall to the ground will be the same for different masses. This can be observed experimentally by dropping objects of different masses from the same height and measuring the time it takes for them to reach the ground.
It's worth noting that the above explanation is a simplified model and neglects factors such as air resistance, which can have a significant impact on the motion of objects falling through the Earth's atmosphere. However, in the absence of air resistance, the acceleration due to gravity is indeed the same for all objects, leading to the observation that objects of different masses hit the ground at the same time.