This document defines units of measurement and discusses density, significant figures, and scientific notation. It states that units of measurement are used to quantify physical quantities that can be measured using devices. It provides the standard SI units for length, mass, time, electrical current, temperature, and amount of substance. The document also explains that density is calculated as mass divided by volume and discusses how to determine the number of significant figures in measurements written in scientific notation or as decimal numbers.

1. Unit Of
Measurement
1.DEFINITION
As any physical quantities that
can be measured by measuring
devices.
1g/cm^3 = lg/mL = 1000kg/m^3
density = mass
volume
Formula :
Length (meter) : m
Mass (kilogram) : kg
Time (second) : s
Electrical current (ampere) : A
Temperature (kelvin) : K
Amount of substance (mole) : mol
n is the exponent
1 until 10
N is the number between
n the value must be an integer
N x 10^n
157 is 3 significant figure
10005 is 5 significant figure
0.00056 is 2 significant figure
0.0005004 is 4 significant figure
7x10^2 is 1 significant figure
Example :
2.DERIVED DIMENSION
Area = length x length
Volume = length x length x length
Speed = length / time
Force = mass x length
Density = mass
3.DENSITY SIGNIFICANT
FIGURE
5.SCIENTIFIC NOTATION
4.UNIT (SI)