If a ball is thrown in the air with a velocity 50 ft/s, its height in feet t seconds later is given by y = 50t - 16t. (a) Find the average velocity for the time period beginning when t = 2 and lasting (i) 0.5 second. ft/s (ii) 0.1 second. ft/s (iii) 0.05 second. ft/s (iv) 0.01 second. ft/s (b) Estimate the instantaneous velocity when t = 2. ft/s