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Science & You
BVIS HANOI (VV)
Phuong & Chi
Measurements are described as physical quantities
There are 7 fundamental units (also called base units)
Units, Quantities, Vectors
Symbol
L/ s/ x
t
I
T
n
m
L
Quantity
Displacement/ Length/ Distance
Time
Current
Temparature
Amount Of Substances
Mass
Luminosity
Unit
Metre
Second
Ampe (Am)
Kelvin
Mole
Kilogram
Candela
Short Unit
m
s
A
K
mol
kg
Φ |
Derieved Units can be written using combinations of base units
Eg: F = ma => N = kgms-2
Vectors & Scalars
Scalar
only has a magnitude (size)
Energy
Time
Distance
Speed
Mass
Density
Vector
has a direction and magnitude (size)
Force
Velocity
Displacement
Acceleration (Decceleration)
Current
Adding vectors is different to adding scalars
Eg: I walk 3m towards and 2m backwards
Resultant Displacement: 1m fowards
3m
2m
1m fowards
Distance: 5m
Adding vectors - finding a resultant vector
End to end
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