Non-uniform motion

Air resistance opposes the motion of the object, resulting in a net force that is less than the object's weight. This reduces the object's acceleration. As speed increases, air resistance increases, further reducing acceleration.

As an object falls, air resistance increases with speed. Eventually, the air resistance equals the object's weight. At this point, the net force is zero, and the object stops accelerating, reaching a constant terminal velocity.

Drag force generally increases as speed increases. A simple model suggests drag force is proportional to the square of the speed (F ∝ v²).

Friction is a force that opposes motion between two surfaces in contact. It acts to slow down or prevent the sliding object from moving. The friction force converts kinetic energy into heat.

Air resistance reduces the horizontal range of a projectile. It opposes the projectile's motion, decreasing its horizontal velocity and causing it to slow down, leading to a shorter distance traveled.

A heavier object experiences a greater gravitational force (weight). Therefore, a greater drag force is required to balance the weight and reach terminal velocity. Since drag force increases with speed, the heavier object needs to fall faster to achieve a larger drag force, resulting in a higher terminal velocity.