College Physics by Openstax Chapter 2 Problem 9

On May 26, 1934, a streamlined, stainless steel diesel train called the Zephyr set the world’s nonstop long-distance speed record for trains. Its run from Denver to Chicago took 13 hours, 4 minutes, 58 seconds, and was witnessed by more than a million people along the route. The total distance traveled was 1633.8 km. What was its average speed in km/h and m/s?

Solution:

The total time of travel is converted to seconds.

t=(13 h ×3600 s1 hr)+(4 mins ×60 s1 min⁡)+58 sec⁡t=47 098 seconds\begin{align*} \text{t} & =\left(13\:\text{h}\:\times \frac{3600\:\text{s}}{1\:\text{hr}}\right)+\left(4\:\text{mins}\:\times \frac{60\:\text{s}}{1\:\min }\right)+58\:\sec \\ \text{t} & =47\:098\:\text{seconds} \end{align*}

The total time of travel in hours

 t=(47 098 seconds)(1 h3600 sec⁡)=13.0828 hours \text{t}=\left(47\:098\:\text{seconds}\right)\left(\frac{1\:\text{h}}{3600\:\sec }\right)=13.0828\:\text{hours}

Therefore, the average speed in km/hr is

speed in km/hr=distance traveledtime=1633.8 km13.0828 hr=124.88 km/hr  (Answer)\begin{align*} \text{speed in km/hr} & =\frac{\text{distance traveled}}{\text{time}} \\ & =\frac{1633.8\:\text{km}}{13.0828\:\text{hr}} \\ & =124.88\:\text{km/hr} \ \qquad \ \color{DarkOrange} \left( \text{Answer} \right) \end{align*}

And the average speed in m/s is

speed in m/s=1 633 800 m47 098 s=34.689 m/s  (Answer)\begin{align*} \text{speed in m/s} & =\frac{1\:633\:800\:\text{m}}{47\:098\:\text{s}} \\ & =34.689\:\text{m/s} \ \qquad \ \color{DarkOrange} \left( \text{Answer} \right) \\ \end{align*}
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