When an object is dropped from a height and falls freely under the influence of gravity (ignoring air resistance), its velocity decreases at a constant rate due to the acceleration caused by gravity.
The acceleration due to gravity near the surface of the Earth is approximately 9.8 meters per second squared (9.8 m/s²). This value is denoted by the symbol "g." When an object is in free fall, it experiences a constant downward acceleration equal to the acceleration due to gravity.
As the object falls, gravity pulls it downward, causing its velocity to increase initially. However, the gravitational force acting on the object is also responsible for continuously changing its velocity. The force of gravity accelerates the object in the downward direction, causing its velocity to change by a constant amount each second.
This constant change in velocity over time results in a linear decrease in velocity. The object's velocity decreases because the acceleration due to gravity is directed opposite to the object's initial velocity. As the object continues to fall, the acceleration due to gravity remains constant, leading to a constant rate of decrease in velocity.
This phenomenon is described by Newton's laws of motion, specifically the second law (F = ma), where the net force acting on the object is the force of gravity (mg), and the resulting acceleration is g. The negative sign in the equation arises because the acceleration due to gravity is in the opposite direction to the object's initial velocity.
In summary, an object's velocity decreases at a constant rate when dropped from a height due to the constant acceleration caused by gravity, as described by Newton's laws of motion.