### Home > CALC > Chapter 5 > Lesson 5.1.3 > Problem5-29

5-29.

Kwok is standing on top of a $160$-foot building and throws a tennis ball straight up with an initial velocity of $24$ ft/sec.

$h(t) = −16t^2 + v_0t + s_0$

1. How far up does the tennis ball go before it turns around and starts to come down?

The tennis ball turns around when $v(t) = 0$.

2. How fast is it going when it hits the ground below?

Evaluate $v$(time of impact). Let $h(t) = 0$ to find the time of impact.