1. As a snowball melts, its surface area and volume decrease. The surface area, S, in square centimeters is modelled by the equation S = 4r² where r is the radius, in centimeters. The volume, V, in cubic centimeters, is modelled by the equation V = 4/3r³.

a) Determine the average rate of change of the surface area and of the volume as the radius decreases from 26 cm to 18 cm.

b) Estimate the instantaneous rate of change of the surface area and volume when the radius is 7 cm.

c) From a) and b), how the average rate of change compare with the instantaneous rate of change.

2. A soccer ball is kicked into the air such that its height, h, in meters, after time, t, in seconds, can be modelled by the function h(t) = -4.9t² + 18x + 1.5, 0 t 3.755.

a) Calculate the average speed of the ball using two times of your choosing. The times has to be between 0 and 3.755 s.

b) Calculate the instantaneous speed of the soccer ball at time of your choosing. The times has to be between 0 and 3.755 s.