unit 1 physical quantity Flashcards
what are base quantity
quantities that cannot be defined in terms of other physical quantities
examples of base quantity
mass (kg) , temperature (K) , length (m) , current (A) , time (s)
what are derived quantity
quantities that can be derived from the base quantities through multiplying/dividing them
examples of derived quantity
speed (m/s) , volume (m^3) , density (kg/m^3)
prefixes ( multiplies)
giga ( 10^9)
mega(10^6)
kilo(10^3)
prefixes ( sub-multiplies)
deci (10^-1)
centi (10^-2)
mili (10^-3)
micro (10^-6)
nano (10^-9)
what are some instruments to measure length
measuring tape , metre ruler , digital calipers , digital ,micrometer screw gauge
precautions to make when measuring length
avoid parallax error ( when the eye of the observer is not perpendicularly to or direct above the rule)
avoid end error by checking the physical condition of the ruler
avoid zero error( when the measuring instrument does not start from exactly zero
digital calipers
inside jaws - measuring internal length of an object
outside jaws - measuring external length of an object
tail - measuring the depth of an object
locking screw - to ensure that the jaws do not move apart
digital display - to show numerical value
measuring range of instruments
metre ruler - 0 to 1m
measuring tape - 0 to several metres
digital calipers - 0 to 15cm
digital micrometer screw gauge - 0 to 2.5cm
one oscillation
when a pendulum completes to and fro motion
period
the period is the time taken for the pendulum to complete one oscillation
random error
human reaction time
factors affecting the period of pendulum
length of the pendulum :
as the length increases , the period increases
as the length decreases, the period decreases
factors that does not affect the period of pendulum
mass of bob
amplitude of oscillation( the angle of oscillation)
