Chapter 1.5, Problem 40PE

For Exercises 39–42, use the model $s=-\frac{1}{2}g{t}^2+v_{0}t+s_0$

with $g=32{\text{ ft/sec}}^2$

or $g=9.8{\text{ m/sec}}^2$

. (See Example 3)

At the time of this printing, the highest vertical leap on record is 60 in., held by Kadour Ziani. For this record-setting jump, Kadour left the ground with an initial velocity of $8\sqrt{5}$ ft/sec.

a. Write a model to express Kadour’s height (in ft) above ground level t seconds after leaving the ground.

b. Use the model from part (a) to determine how long it would take Kadour to reach his maximum height of 60 in. (5 ft). Round to the nearest hundredth of a second.