Physics – 1.2 Motion | e-Consult

When an object is dropped in a uniform gravitational field, it accelerates downwards due to the force of gravity. Initially, the only force acting on the object is gravity, resulting in a constant downward acceleration (approximately 9.8 m/s² near the Earth's surface). As the object's speed increases, the force of air resistance also increases. Air resistance acts in the opposite direction to the motion, opposing the downward acceleration.

Eventually, the force of air resistance becomes equal to the force of gravity. At this point, the net force acting on the object becomes zero, and the object stops accelerating. The object then continues to fall at a constant speed. This constant speed is called the terminal velocity.

Terminal velocity is reached when the magnitude of the gravitational force is balanced by the magnitude of the air resistance force. This occurs when the object's shape and size create sufficient air resistance to counteract the force of gravity. Factors affecting terminal velocity include the object's mass, shape, and surface area. A larger surface area generally results in a lower terminal velocity.