10m = a physical quantity Physical Quantities are made up of two parts :- - number - unit Units: Giga = 10^9 Mega = 10^6 Kilo = 10^3 Deci = 10^(-1) Centi = 10^(-2) Milli = 10^(-3) Micro = 10^(-6) Nano = 10^(-9) There are many Units so a common system of units is used called the SI Units. SI Units = base units for measuring mass, time, length .etc. Mass SI Unit = kg - affects how objects behave in two ways i) The greater the mass of an object, the stronger the gravitational pull Earth has on it. ii)The greater the mass, the greater is the resistance to change in motion. Time SI Unit = second 1 second = the frequency of an oscillation in the nucleus of a caesium atom Length SI Unit = m 1 metre = The length traversed by light in 1/299792458 th of a second.
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