The deck of a bridge is suspended 235 feet above a river. If a pebble falls off the side of the bridge, the height, in feet, of the pebble above the water surface after t seconds is given by y = 235 − 16t^2. Required:
a. Find the average velocity (in ft/s) of the pebble for the time period beginning when t = 2 and lasting the following amount of time.

1. 0.1 sec:
2. 0.05 sec:
3. 0.01 sec:

b. Estimate the instantaneous velocity (in ft/s) of the pebble after 3 seconds. ft/s.