Explanation
Convert the object's speed from feet per second to feet per hour:
\(8\frac{{ft}}{s} \times 60\frac{s}{{min}} \times 60\frac{{min}}{{hr}} = 28,800\frac{{ft}}{{hr}}\)
Then multiply by the number of hours:
\(28,800 \frac{ft}{hr} \times 5 hr = 144,000 ft\)