It is what help us to understand our world better and to use this understanding for the benefits of people and environment. It involves the wide range of ideas and areas of investigations. It plays and important part in the the home, leisure, medicine and communication.
As with science it involves observations and experiments which are used to discover the relationship between things.
Who are the physicist ?
They try to make sense of relationships by developing theories and models. These theories are able to predict further behavior which can then be tested by experiments.
Physical quantities / Metric system
Note: Some people may think physics is really hard and confusing , that's right it is and that's what i still think, but remember its like a challenge and you need to refer this to real life situations and fight it to beat it. Just think it as a video game where you have evil bosses as formulas and equations and you are the ultimate formula killer etc.... have fun with something and you will learn. You know how i used to study ? . Well basically i wrote down a couple of problems in each A4 paper and then act as i am a super genius that is sent to earth to crack the most difficult equation. Then i used to make sounds say words and then solve and fall asleep. the next morning when it was exam time and the same kind of question appeared i was like " wow , it's time for super genius kid" hahah...sounds funny no ? ...but guess what i scored 20/20 in that exam , see what i mean ?...
System international Units - It is the standard system of units to measure all physical quantities , in other words the units in which the answer you write is gonna be in.
Length - Meter (m)
Mass - kilograms (kg)
Time - Seconds (s)
current - Ampere (a)
Temperature - kelvin (K)
Intensity - Candela (Cd)
Amount of substance - Mole (Mol)
Standard Prefix Multiplier
Tera - 10 * 12 ( * = power of)
Giga - 10 * 9
Mega - 10*6
Kilo - 10* 3
Centi - 10*-2
Milli - 10*-3
Nano - 10*-9
Pico - 10*-12
Peta - 10 *15
Femto - 10* -15
Exapmle 1 :
10 pM ----> M
10 x 10 * -12 m = This how you convert Pico Meter to Meter
Step 1: Length
it is the amount of surface for an object. For regular shapes we use formula for each shape and for irregular shapes we use grids and the count out the number of grids inside the figure. Thats the final area of that shape.
It is the amount of space a object takes up. The volume of regular objects are calculated by using formula's and of irregular are is found by displacement of water.
Some example of formula's to calculate volume are :
Cube - l2
Cuboid - L x w x h
Prism - Base area x height
Cylinder - TTr2 x height
Cone - 1/3 TTr2 x height
Pyramid - 1/3 base area x height
Sphere - 4/3 TTr3
Volume of irregular object
The volume of irregular objects can be found by using displacement method, for smaller objects a cylinder can be used but for larger objects we use a special equipment called the Eureka Can.
Get a old cylinder can like a tin or a measuring cylinder if you have one. Choose the different types of objects you wanna find the volume of and then fill the cylinder with water of about 250 ml or 150 ml. Place the object in the water and then note down the new volume reading on the cylinder.
Formula = Final Measuring - Initial measuring
your new measure - 250 or 150
explore more ways and try to make your own formula to find other ways to find volumes of objects.
Step 2: Mass and Weight
Is how much Matter is in an object. It depends on the object size and the material it is made up of. Unit is in Kilograms (Kg). remember mass never changes , so if your mass on earth is 710 N and on moon will mass the same 710 N.
It is the gravitational pull on an object it is depended on the objects size and what it is made up of. Basically it means how much the power is used by the earths magnet to pull you. Units is Newtons (N).
To calculate weight :
W = Mass x Gravity pull where Gravity is = 10m/s2
So next time when someone ask you weight tell them that it's 710 or whatever Newtons and they will be shocked wondering what that it and how them that you know physic.
Step 3: Significant Figures
1. All zero digits placed in between non- zero digits are significant figures.
e.g - 101 - 3 s.f
2. All non- zero digits are significant
e.g - 1234 - 4 s.f
3. Zero placed after decimal place and before non zero digit are not significant.
e.g. - 0.01 - 1 s.f
4. Zeros placed after non zero digit behind the decimal points are significant.
e.g - 0.010048 - 5 s.f
5. Zeros at the end of a number are significant only if they are indicated to be so through the use of scientific notation.
e.g - 8200 - may have different significant figures.
(i) 8.2 x103 = 2 s.f