Mathematics

Problem

A hiker’s elevation

E

(in meters) is recorded as a function of time

\tau

measured in hours. A GPS device displays an instantaneous vertical speed of

1.8\ \text{m/s}

. Assuming the device reports

\dfrac{dE}{dt}

where

t

is in seconds, what is

\dfrac{dE}{d\tau}

expressed in kilometers per hour? (Use

1\ \text{km}=1000\ \text{m}

and

1\ \text{hr}=3600\ \text{s}

.) a)

0.648\ \text{km/hr}

3.24\ \text{km/hr}

6.48\ \text{km/hr}

64.8\ \text{km/hr}