Kinematics

length

common units: metre, mile, inch
si unit: metre
symbol: m

mass

common units: pounds, kg ounce
si unit: kilogram
symbol: kg

time

common units: second, minutes, hours
si unit seconds, s

electric current

ampere, A

temperature

kelvin, K

amt of substance

mole, mol

precision (instruments)
measuring tape

measuring range: more than 1 metre
precision: 1 cm or 10mm

metre rule

measuring range: 10 cm to 1m
precision: 0.1cm or 1mm

vernier caliper

measuring range: ~2cm to ~10cm
precision: 0.01cm or 0.1mm

micrometer screw gauge

measuring range: less than 2cm
precision: 0.001cm or 0.01mm

types of errors

human reaction time, background noise and mechanical vibration

definition of distance

distance is the length covered by a moving object regardless of the direction, a scalar quantity
unit: m

definition of displacement

displacement is the length measured in a straight line in a specific direction, a vector quantity
unit: m

definition of speed

speed is the rate of change of distance with respect to time or distance moved per time, scalar quantity
unit: m/s
speed = distance/ time
average speed = total distance/ total time taken

definition of velocity

velocity is the rate of change of displacement with respect to time, vector quantity
unit: m/s
velocity = rate of change of displacement = displacement/ time taken
average velocity = total displacement/ total time taken

definition of acceleration

rate of change of velocity with respect to time
acceleration = [final velocity - initial velocity]/ time taken
unit: m/s^2
as acceleration is a vector quantity, it changes when its magnitude and/or direction changes