### Home > CALC > Chapter 5 > Lesson 5.2.4 > Problem5-95

5-95.
1. When Regit hit his golf ball at the 18th hole, it went straight up in the air! Homework Help ✎

1. If he hit it with an initial velocity of 144 feet per second, write an equation for the ball's velocity, v(t), at time t. Assume the gravitational constant a(t) = −32 ft/sec2 and that Regit hit the ball while it was on the ground.

2. When was the ball at rest? What is happening at that point in time?

3. What was the maximum height of the ball?

$s(t)=\frac{1}{2}at^{2}+v_{0}t+s_{0}$

Find s(t). Then find v(t).

s(t) = −16t² + 144t + 0
v(t) = −32t + 144

The ball is at rest whenever the velocity is equal to zero. What is happening to the ball at these times?

Remember that the ball has a velocity of zero at the peak of its parabolic flight.