What is drag? in what situations might it act on the force of gravity?

Drag is a force of resistance that acts in fluid motion. When there is relative motion with respect to a fluid, a drag force acts in the opposite direction to the motion. Drag depends on viscosity, compressibility of the fluid and mass of the object.

When the sum of drag force and buoyant force are equal to the downward force of gravity, the object falls with a constant velocity known as terminal velocity.

answercollision;