If a ball is thrown straight up into the air with an initial velocity of $50$ ft/s, its height in feet after $t$ second is given by $y = {50}t - 16t^2$. Find the average velocity (include units, help (units)) for the time period begining when $t = 2$ seconds and lasting

(i) $0.5$ seconds
Average velocity:

(ii) $0.1$ seconds
Average velocity:

(iii) $0.01$ seconds
Average velocity:

Finally based on the above results, guess what the instantaneous velocity of the ball is when $t =2$.
Average velocity: