Question

Ms.Morton can run 2 miles in 16 minutes and 15 seconds. How fast is she running in miles per hour?(Using dimensional analysis)

Answer 1

Ms.Morton is running at 7.38 miles/hour

Step-by-step explanation:

distance = 2 miles

time = 16 minutes and 15 seconds

We need one unit for the time. Converting seconds to minute:

60 seconds = 1 minute

Using dimensional analysis:

`\begin{gathered} 15\text{ seconds}*\frac{1\text{ minutes}}{60\text{ seconds}} \\ =\text{ 0.25 minutes} \\ \text{time = 16 minutes 15 seconds} \\ \text{time = 16 mins + 0.25 mins = 16.25mins} \end{gathered}`

speed = distance/ time

The speed in miles per hour:

60 minutes = 1 hour

`\begin{gathered} \text{speed = }\frac{2miles}{16.25\text{ minutes}} \\ =\text{ }\frac{2miles}{16.25\text{ minutes}}*\frac{60\text{ minutes}}{1\text{ hour}} \\ =\text{ }\frac{120\text{ miles}}{16.25\text{ hour}} \\ =7.38\text{ miles/hour} \end{gathered}`

Ms.Morton is running at 7.38 miles/hour