1.3 how do we measure physical quanities + 1.4 what are scalars and vectors Flashcards
what measuring instruments can be used to measure length
meter rule, measuring tape, digital calipers, micrometer screw gauge
meter rule
- commonly used to measure length
- can measure lengths of up to 1m
measuring tape
- commonly used to measure length
- suitable for measuring distances longer than 1m
digital calipers
-measures the internal and external diameter of an object accurately
parts of a digital calipers
inside jaws
outside jaws
locking screw
digital display
zero button
scale
tail
(digital calipers) inside jaws
measures the internal diameter of an object
(digital calipers) outside jaws
measures external diameter or width of an object
(digital calipers) digital display
shows the numeric value
(digital calipers) zero button
resets the displayed length back to zero
(digital calipers) tail
measures the depth of an object
digital micrometer screw gauge
- measures object too small to be measured by digital calipers
parts of a digital micrometer screw gauge
anvil
splindle
scale
ratchet
thimble
digital display
zero button
how does a digital micrometer screw gauge work
- the object is placed between the anvil and spindle
- the ratchet is turned until the spindle is in contact with the object
(ensure that the object is held tightly between the anvil and spindle. do not tighten ratchet too much)
(digital micrometer screw gauge) ratchet
can be turned to adjust the spindle so that the spindle is in contact with the object
(digital micrometer screw gauge) digital display
used to show the numeric value
(digital micrometer screw gauge) zero button
used to reset the displayed length back to zero
precision of an instrument
the smallest until an instrument can measure
smallest division measured by measuring tape
0.1cm (1mm)
smallest division of meter rule
0.1cm (1mm)
smallest division of digital calipers
0.001cm (0.01mm)
measuring range of digital calipers
0 to 15 cm
smallest division of digital micrometer screw gauge
0.0001cm or 0.001mm
oscillation
a complete to and fro motion
pendulum use
-used to measure time
motion of pendulum
moves back and forward at regular intervals
parts of pendulum
consists of a bob (heavy metal ball) that is attached to one end of a string
period of a simple pendulum
time taken for one complete oscillation
pendulum clock
used to measure time using a pendulum’s periodic swing
clocks and stopwatches
oscillations of springs and natural vibration of crystals are period motion that can be used to keep time
how long is human reaction time
0.3-0.5 sec
scalar quantities
physical quantities that only have magnitude
vector quantities
physical quantities that have both magnitude and direction
example of scalar quantities
-distance
-speed
-mass
-energy
-time
example of vector quantities
-displacement
-velocity
-acceleration
-force
-weight
distance
total length covered by a moving object regardless of direction of motion
displacement
distance measured in a straight line in a specific direction
speed
distance moved per unit time
velocity
rate of change of displacement
SI unit if speed
meter per second (m/s)
SI unit for velocity
meter per second (m/s)
speed formula
distance/time taken
velocity formula
displacement/time taken
