Chapter 5.7, Problem 39ES

Assume that a free-fall model applies. Solve these exercises by applying Formulas $\left(15\right)$ and $\left(16\right)$ . In these exercises take $g=32{\text{ ft/s}}^{\text{2}}$ or $g=9.8{\text{ m/s}}^{\text{2}}$ , depending on the units.

A projectile is launched vertically upward from ground level with an initial velocity of $112\text{ ft/s}$ .

(a) Find the velocity at $t=3\text{ s}$ and $t=5\text{ s}$ .

(b) How high will the projectile rise?

(c) Find the speed of the projectile when it hits the ground.