RESUME PHYSIC SEMESTER GASAL

CHAPTER I MEASUREMENT
A. Definition of Measurement
Measuring is to compare a physical quantity of an object with similar quantity used as a unit.
Measuring systems :
1. The British system : gallon for water
Yard for thread
Inch for pipe
2.Since 1700 some scientists have used measuring system is called The metric system.
In 1960 the metric system was used and officially called the international system or SI units.

QUANTITIES AND UNITS
a physical quantity is a quantity which can be measured. Such as length, mass, and so on.
The quantity which cannot be measured is not a physical quantity such as sadness, love and loyalty.
The physical quantity is divided into : fundamental quantity and derived quantity .
The fundamental quantities are the quantities that has been defined their own units.
In 1971 the international system uses the 7 fundamental quantities as follows :
Fundamental quantities : Length( m )
Mass ( kg )
Time ( s )
Temperature ( kelvin = K )
Luminous Intensity ( Candela =Cd)
Amount of substance ( Mole = mol)
Electric current ( ampere = A )


Derived quantities are the quantities that derived from these fundamental quantities.
such as : volume,density,velocity,force,work and so on.


I. LENGTH
Length represents the distance between two points.
Length uses SI unit in meter ( m ). One standard meter is the same as the distance
traveled by light in a vacuum in 1/ 299.792.458 second
some tools for measuring length :

a. ruler.
b. a meter tape
c. vernier caliper.( jangka sorong )
d. srew micrometer ( micrometer skrup )
II. MASS
Every substance consists of materials.
Mass is the amount of materials in the substance.
Mass is not the same as weight.
The mass of an object is determined by the contained materials in it , and it is fixed although the objects position changes.
Weight depends on the position of the object on the earth and is affected by the gravitational force.
In SI, mass uses basic unit kilogram ( kg ),while weight is Newton ( N ).
The mass of an object is measured with lever balance or balance
Weight is measured with spring balance/ dynanometer
III. TIME
Time is the duration between two events.
The SI unit for time is second ( s).
One standard second is the time needed by Cesium atom to vibrate 9,172,631,770 times.
For long events, time is stated in larger units such as minute, hour , day, year, centaury , etc. But for a fast event, you can use millisecond ( ms ), microsecond (μs), and nanosecond ( ns ).
II. TEMPERATURE
The temperature is the degree of hotness and coldness of an object.
The tool for temperature is a thermometer.
Unit of temperature in SI unit is Kelvin