Monday, August 10, 2015

Physical Quantities and Units | 9702 Physics Summary Notes

  • 1. Physical Quantities and Units | 9702 Physics Summary Notes



 

1.1 Physical Quantities

· A physical quantity is made up of magnitude and unit



1.2 Base Units

· The following are base units:
Quantity
Basic Unit
Name
Symbol
Name
Symbol
Mass
m
Kilogram
kg
Length
l
Meter
m
Time
t
Second
s
Temperature
T
Kelvin
K
Electric Current
I
Ampere
A





· All units (not above) can be broken down to base units

· Homogeneity can be used to prove equations.

· An equation is homogenous if base units on left hand side are the same as base units on right hand side.

· This may not work every time due to the fact that it does not take pure numbers into account (Ek formula)



1.3 Multiples and Submultiples

Multiple
Prefix
Symbol
1012
Tera
          T
109
Giga
          G
106
Mega
          M
103
Kilo
          k
Submultiple
Prefix
Symbol
10-3
Milli
          m
10-6
Micro
          μ
10-9
Nano
          n
10-12
Pico
          p

 

 

1.4 Estimations

Mass of a person
70 kg
Height of a person
1.5 m
Walking speed
1 ms-1
Speed of a car on the motorway
30 ms-1
Volume of a can of a drink
300 cm3
Density of water
1000 kgm-3
Density of air
1 kgm-3
Weight of an apple
1 N
Current in a domestic appliance
13 A
e.m.f of a car battery
12 V
Hearing range
20 Hz to 20,000 Hz
Young’s Modulus of a material
Something  1011






1.5 Scalar and Vector

· Scalar: has magnitude only
e.g. speed, energy, power, work, mass, distance

· Vector: has magnitude and direction, can be –ve
e.g. displacement, acceleration, force, velocity, momentum, weight, electric field strength



1.6 Vectors






3 comments:

  1. You guys copied it from znotes

    ReplyDelete
    Replies
    1. Yes and this was done with permission from the admin of znotes. Proper credit is given at
      http://physics-ref.blogspot.com/2014/05/physics-9702-notes-worked-solutions-for.html


      At some point in time, we were in contact and agreed to share the stuffs. This was some times before znotes has become what it is now.

      Also, anyone can help if they wish.
      See
      http://physics-ref.blogspot.com/2016/01/participating-to-physics-reference-blog.html

      Delete

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