What two factors primarily affect the force of air resistance on a falling object?

The force of air resistance, also known as drag, on a falling object is primarily influenced by the object's frontal area and speed.

Frontal area refers to the surface area of the object that faces the direction of motion. A larger frontal area results in greater air resistance because more air molecules collide with the object as it falls through the air. This is why, for example, a parachute generates significantly more air resistance compared to a small ball – the parachute has a larger surface area exposed to the airflow.

Speed is the second crucial factor affecting air resistance. The drag force increases with the square of the speed of the object. This means that as an object falls faster, the air resistance it encounters increases dramatically. This quadratic relationship signifies that even small increases in speed lead to substantial increases in drag force.

Together, these two factors – frontal area and speed – determine the extent of air resistance experienced by a falling object, influencing its acceleration and overall motion during free fall. Other options, while they might affect various properties of an object, do not directly correlate with how air resistance acts during the fall.