Physics for Scientists and Engineers 3E by R. Knight, P1.26


Using the approximate conversion factors in Table 1.5, convert the following to SI units without using your calculator.

a. 20 ft

b. 60 mi

c. 60 mph

d. 8 in


Solution:

Part a

\displaystyle 20\:ft\approx \left(20\:ft\right)\left(\frac{1\:m}{3\:ft}\right)\approx \:7\:m         ☚

Part b

\displaystyle 60\:miles\approx \left(60\:miles\right)\left(\frac{1\:km}{0.6\:miles}\right)\left(\frac{1000\:m}{1\:km}\right)\approx 100,000\:m         ☚

Part c

\displaystyle 60\:mph\approx \left(60\:mph\right)\left(\frac{1\:m/s}{2\:mph}\right)\approx 30\:m/s          ☚

Part d

\displaystyle 8\:in\approx \left(8\:in\right)\left(\frac{1\:cm}{1/2\:in}\right)\left(\frac{10^{-2}\:m}{1\:cm}\right)\approx 0.2\:m          ☚