Chapter 8, Problem 58SGR

To determine

To find: The time boulder will take to hit the water.

Answer to Problem 58SGR

The time taken by the boulder is: $2$ seconds.

Explanation of Solution

Given information:

The given height is 64 feet and equation for distance is $d=16t^2$

Calculation:

Here the equation is:

  $d=16t^2$

The strategy is to solve the equation considering the height as 64 feet.

Put $d=64$ in the above equation:

  $\begin{array}{l}64=16t^2\\ \text{The equation can be solved as below:}\\ {\text{64=16t}}^2\\ \frac{16t^2}{16}=\frac{64}{16}\left[\text{Divide both sides by 16}\right]\\ t^2=4\\ t=\sqrt{4}\\ t=-2,2\end{array}$

Since time cannot be negative, therefore the boulder will take $2$ seconds to hit the water.