Chapter 4, Problem 19SGR

To determine

To find: The ball to hit the ground.

Answer to Problem 19SGR

.The time taken by the ball to hit the ground back is $7.5\text{seconds}$ .

Explanation of Solution

Given information:

A baseball is hit upward at $120$ feet per second.

Calculation:

The formula is

  $h\left(t\right)=v_{0}t-16t^2$

The velocity is 120 feet per second .

  $v_0=120$

Since the ball hit back the ground .

Substituting value of $h$ and $v_0$ , we get .

  $\begin{array}{c}0=120t-16t^2\\ 16t^2=120t\\ 2t=15\\ t=7.5\end{array}$

Using the fact that time is not equal to zero. The time taken by the ball to hit the ground back is $7.5$ second.

.

Therefore, the time taken by the ball to hit the ground back is $7.5\text{seconds}$ .