## System Dynamics 3rd Edition

$34.09\ mph$
$Distance$ $1\ mile=5280 ft$ $1\ yard = 3 ft$ $1\ ft= 12 in$ $Time$ $1\ hour= 60 min$ $1\ minute= 60 sec$ We use unit conversions to find: $\frac{50 ft}{1 sec}\times\frac{1 mi.}{5280 ft}\times\frac{60 sec}{1 min}\times\frac{60 min}{1 hr}=\frac{180,000 mi}{5280 hr}\approx \ 34.09 mph$