Answer
The instantaneous velocity is 100 m/s directed downward.
The average velocity is 50 m/s directed downward.
It falls 500 m.
Work Step by Step
From page 46, using g =$10 \frac{m}{s^{2}}$, v = gt = 100 m/s.
Averaging the initial velocity of zero with the final velocity of 100 m/s, we obtain 50 m/s, downward.
We can find how far it drops by multiplying the average velocity and the time.
$$d = (50 \frac{m}{s})(10 s) = 500 m$$
Alternatively, we could use an equation from page 48, $d = \frac{1}{2}gt^{2}$.
Both approaches give the same answer.