Chapter 2 - Quantities And Units Flashcards
What is a physical quantity ?
a physical quantity is a property of an object or of a phenomenon that can be measured
Whats the base unit for length ?
Metre - m
Whats the base unit for mass ?
Kilogram - kg
Whats the base unit for time ?
Second - s
Whats the base unit for electric current ?
Ampere = A
Whats the base unit for temperature ?
Kelvin - K
Whats the base unit for amount of substance ?
Mole - mol
Whats the factor for peta - P ?
10*15
Whats the factor for tera - T ?
10*12
Whats the factor for giga - G ?
10*9
Whats the factor for mega - M ?
10*6
Whats the factor of kilo - k ?
10*3
Whats the factor for deci - d ?
10*-1
Whats the factor of centi - c ?
10*-2
What’s the factor of milli - m ?
10*-3
Whats the factor of micro - weird u ?
10*-6
Whats the factor of nano - n ?
10*-9
Whats the factor of pico - p ?
10*-12
What’s the factor of femto - f ?
10*-15
Whats a scalar quantity ?
A scalar quantity has magnitude (size) but no direction
How do you add/subtract scalar quantities ?
You can only add scalar quantities if they are the same unit for e.g. you can’t add 1min + 30secs and do 1+30 - you would have to convert rather 1min into secs then add
Can you divide and multiply scalar quantities?
Yes you can and it can have different units - the units don’t have to be the same for you to subtract and multiply 2 scalar quantities
Whats a vector quantity ?
A vector quantity has magnitude and direction
Whats distance and displacement measured in ?
Metres - m
However displacement is a vector quantity and distance is a scalar quantity
What do you do when 2 vectors are parallel ?
If they are parallel (act in the same line and direction), you just add them together to find the resultant vector
What do you do when there are 2 vectors that are anti parallel (they act in the same line but in opposite directions ) ?
Subtract the bigger one from the smaller one and the resultant vector will be acting in the direction of the bigger force
