The two factors that act on parachutes are gravity and air resistance, which is also called drag. Gravity acts as a force to pull parachutes down to the surface of the Earth, while air resistance generates movement in the opposite direction of the falling parachute, and essentially pushes the parachute upward.
The influence of gravity and air resistance depend on several factors, including the shape of the parachute, size and weight of the parachutist, and the speed at which the parachute is falling. Generally, the smaller and lighter an object is, the rate at which it falls through the air is slower compared to an object of a larger size. This means that air resistance acts with a greater force on the smaller and lighter object, helping it remain in the air for longer periods of time. While air resistance works to keep parachutes in the air, gravity has the opposite effect. Gravity essentially pulls parachutists downwards as soon as they exit the plane from which they are launched. As with air resistance, gravity depends on several factors, including the weight of the parachutist and shape of the parachute. The force of gravity that acts on an object is also called its weight, and changes as the parachute moves through the air.