Chapter 1 (Physical quantities, units and measurements) Flashcards
What is a physical quantity
A physical quantity is a quantity that can be measured consisting of a numerical magnitude and unit
Prefix multiples with their Factor and symbol
Tera- (10 to 12) (T)
Giga- (10 to 9) (G)
Mega- (10 to 6) (M)
kilo- (10 to 3) (k)
Prefix sub-multiples with their factor and symbol
Deci- (10 to -1) (d)
Centi- (10 to -2) (c)
Milli- (10 to -3) (m)
Micro- (10 to -6)
Nano- (10 to -9) (n)
What can be used to measure length
metre rule
digital calipers
measuring tape
digital micrometer screw gauge
What is the size of
i) an atom
ii) width of human hair
iii) length of football field
iv) radius of earth
i) 10 to -10
ii) 10 to -4
iii) 10 to 2
iv) 10 to 7
Characteristics of measuring tape
-measure zero to several metres
-smallest division is 0.1 cm or 1 mm
-used to measure a persons waist
characteristics of metre rule
-measure zero to one metre
-smallest division is 0.1 cm or 1 mm
-used to measure height of table
characteristics of digital caliper
-measure zero to 15 centimetres
-smallest divisions is 0.001 cm or 0.01 mm
-used to measure diameter of test tube
characteristics of digital micrometer screw gauge
-measure zero to 2.5 centimetres
-smallest divisions is 0.0001 cm or 0.001 mm
-used to measure diameter of a wire
How to avoid parallax errors
line of sight should be perpendicular to the measurement
What is an oscillation
A complete to and fro motion
What is the period of a pendulum
The time to complete one complete oscillation
Why do we take readings to the nearest one decimal place for stopwatches
-most stopwatches can be measured to a precision of 0.01s
-stopwatches need to be started and stopped by hand
-causes random human error
-reaction time is about 0.3-0.5 s for most people
What are scalar quantities
scalar quantities are quantities that only have magnitude
What are vector quantities
Vector quantities are quantities that have magnitude and direction
