An object falling straight down without air resistance is said to be exhibiting freefall.

Here's why:

* Freefall means the only force acting on the object is gravity.

* Air resistance is a force that opposes motion through the air. When it's absent, the object experiences pure gravitational acceleration.

This is a simplified model, as in reality, air resistance is almost always present. But in physics, studying freefall helps us understand the fundamental effects of gravity.