## AP Physics

Presentation of chapter 1 Frank Chen Period 5 1.4 Conversion of Units In 1960, an international committee established a set of fundamental quantities of science which is called SI. There is also a set of U.S. customary units, theses are some examples of convert U.S. into SI: 1 mile = 1609 m = 1.609 km; 1 m = 39.37 in. = 3.281 ft; 1 ft = 0.3048m = 30.48 cm; 1 in = 0.0254m = 2.54 cm Conversion Factors The method to convert the different units into the required unit Ex. 13.0 in. = (15 in.)(2.54 cm/1in.) = 38.1 cm 1.5 Order of magnitude Order of Magnitude is an scientific method use symbol ?~?to estimate a magnitude round into one digit and expressed in scientific notation. Ex. 0.00054m ~ 10^-4m 3600m ~ 10^3m 4 1.6 Uncertainty in Measurements