College Physics Problem 1.1


The speed limit on some interstate highways is roughly 100 km/h.
(a) What is this in meters per second?
(b) How many miles per hour is this?


Solution:

Part a

\displaystyle 100\:km/hr=\left(100\:\frac{km}{hr}\right)\left(\frac{1000\:m}{1\:km}\right)\left(\frac{1\:hour}{3600\:s}\right)=27.77\:m/s

Part b

\displaystyle 100\:km/hr=\left(100\:\frac{km}{hr}\right)\left(\frac{1\:mile}{1.609\:km}\right)=62\:mi/hr