3.2.2—The motion of objects in a uniform gravitational field with air resistance

For a falling object, resultant force is mg minus upward resistance. As speed grows, resistance can grow and reduce the downward acceleration.

Write m dv/dt=mg−R(v), state the drag model and use signs consistently. The no-drag constant-g solution is only an ideal comparison.

With linear drag R=kv, acceleration decreases from g at release as v increases.

Gravity does not switch off when drag appears; drag changes the resultant and therefore acceleration.