To find out how many hours it would take for the falcon to fly 52,800 feet at a constant speed of 68 mph, you need to ensure that the units are consistent. Since the speed is given in miles per hour, you need to convert the distance from feet to miles.
1 mile = 5280 feet
To convert 52,800 feet to miles:
\[ \text{Miles} = \frac{52800 \text{ feet}}{5280 \text{ feet/mile}} = 10 \text{ miles} \]
Next, use the formula:
\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \]
Substituting the values:
\[ \text{Time} = \frac{10 \text{ miles}}{68 \text{ mph}} \approx 0.147 \text{ hours} \]
Therefore, you would need to convert the units of distance from feet to miles.
So the answer is: ** miles**.