An object falls with constant acceleration towards the center of the Earth due to the force of gravity. Gravity is the attractive force between two objects with mass, and it acts towards the center of mass of the Earth. When an object is in the vicinity of the Earth's surface, the force of gravity is approximately constant.
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. In the case of a falling object near the Earth's surface, the only significant force acting on it is the force of gravity. Therefore, the acceleration of the object is determined by the gravitational force.
The force of gravity on an object near the Earth's surface is given by the equation F = mg, where F is the force of gravity, m is the mass of the object, and g is the acceleration due to gravity. The value of g is approximately 9.8 meters per second squared (9.8 m/s²) near the Earth's surface.
Since the force of gravity is constant for objects of the same mass near the Earth's surface, the acceleration of all falling objects is also constant and equal to the acceleration due to gravity (g). This means that all objects, regardless of their mass, will experience the same acceleration as they fall towards the center of the Earth. This constant acceleration causes the object to fall with increasing speed over time.