Question

A ball is thrown vertically upward with an initial velocity of 128 feet per second, the ball’s height after t second is s(t) = 128t – 16t².Find the average velocity from 2 to 4 seconds.

Answer 1

avg velocity is (total distance)/(total time)

so, that would be

(s(4)-s(2))/(4-2)

Answer 2

derivative V:

V (average) = dx/dt = 128 - 16 x 2 t^2-1

= 128 - 32t

substitute the time given

t = 4:

128 - 32 x 4 = 0
t=0

t = 2:

128 - 32 x 2 = 64
t=64