A student dropped a textbook from the top floor of his dorm and it fell according to the formula s(t)=16t^2+8 sq root t, where t is the time in second and s(t) is the distance in feet from the top of the building.

a.) write a formula for the average velocity of the ball for t near 9.

b.) find the average velocity for the time interval beginning when t=9 with duration 1 seconds, 0.5 seconds, and 0.05 seconds.

c.) what is your estimate for the instantaneous velocity of the ball at t=9