Example 5: Parabola

A ball thrown upward with initial velocity b ft per sec will be at a height

y = bt - 16t²

feet after t seconds. Find the velocity at time t. Let t be real and Δt ≠ 0, infinitesimal.

At time t sec,

v = y' = b - 32t ft/sec.

Both functions are graphed in Figure 2.1.7.

Figure 2.1.7