Gravitational acceleration (acting "down") is proportional to mass. Air friction (acting "up") is proportional to the velocity of the object. Terminal velocit

Gravitational acceleration (acting "down") is proportional to mass. Air friction (acting "up") is proportional to the velocity of the object. Terminal velocity is reached when the force of air friction equals the force of gravitational acceleration: gm = nv^2. Since g, n are constants, if m decreases, v decreases.