Question

a ball is thrown into the air with a velocity of 40 ft/s, its height in feet seconds later is given by y=40t-16t^2. a) Find the average velocity for the time period beginning when and lasting (i) 0.5 second (ii) 0.1 second (iii) 0.05 second (iv) 0.01 second (b) Estimate the instantaneous velocity when t=2

Answer 1

v(t) = dy/dt = 40 - 32t
ai). average velocity = (v(0.5) - v(0))/(0.5 - 0) = ((40 - 32(0.5)) - (40 - 32(0)))/0.5 = (40 - 16 - 40)/0.5 = -16/0.5 = -32m / s

ii). average velocity = (v(0.1) - v(0))/(0.1 - 0) = ((40 - 32(0.1)) - (40 - 32(0)))/0.1 = (40 - 3.2 - 40)/0.1 = -3.2/0.1 = -32m / s

iii). average velocity = (v(0.05) - v(0))/(0.05 - 0) = ((40 - 32(0.05)) - (40 - 32(0)))/0.05 = (40 - 1.6 - 40)/0.05 = -1.6/0.05 = -32m / s