A very important example of uniformly accelerated motion, as long as we ignore air resistance, is the vertical motion of an object in a uniform gravitational field, called free fall. Taking down as positive, we can draw graphs of acceleration, velocity and displacement with time. In fact, air resistance is not negligible, and the effect is to reduce the acceleration, velocity and displacement at each point compared to what it would have been without air resistance. Eventually the terminal velocity – maybe 200 m/s - is reached. The acceleration is reduced to zero and the velocity becomes constant.