A body is let go from rest and drops vertically through air of constant density. Which statement about the body's motion is correct?
- AAs it accelerates, its weight decreases so that its acceleration decreases until it travels with constant velocity.
- BIt accelerates initially at $9.8\,\text{m s}^{-2}$ but the drag force increases so its acceleration decreases.
- CIts velocity increases at a constant rate until its velocity becomes constant.
- DThe drag force of the air increases continually and eventually the velocity decreases.