introduction to physics Flashcards
what is physics?
- physics is a branch of science.
uses experiments, measurements
-maths to describe everything in the universe.
-laws to predict everything in the universe
-describes energy and matter
what is energy?
ability to do work
light/kinetic/gravitational/electric/thermal
what is matter?
tiny atoms and particles but also large structures like stars and galaxies
how are energy and matter related?
energy and matter have a relationship that produces laws
what are the two types of physics
theoretical and experimental
what is theoretical physics?
theories of physics.
explains the results of experimental data and observations using maths and scientific concepts
what is experimental physics?
creating a hypothesis (idea) and testing the hypothesis with experiments, observing the results and coming to a conclusion. potentially establishing new scientific laws to understand and predict something.
how does physics link to chemistry?
chemistry involves atoms and molecules this links to molecular physics
how does physics link to architecture?
structural ability of buildings, heating, lighting and cooling of building are all linked to physics
how does physics link to geology?
the study of rocks, radioactive dating of rocks, earthquake analysis and heat transfer in earth
how does biology link to physics?
heat/work/power in human body
what is a quantity in physics
an amount, a measurement of something and its unit
what is the units for length, volume, area, time,mass,speed,energy, charge and resistance
m/m cubed/m squared/s/kg/ (m/s) / j / coloumbs/ ohms
what are SI units
6 main base units that all units are derived from.
what are significant figures
the important values
force (units and equation)
mass x acceleration - newton or kg m/s -2
pressure (units and equation)
force /area - pascal or nm -2
work done (units and equation)
force x distance - joule or Nm
power (units and equation)
energy/time - watt or Js-1
potential difference (units and equation)
energy/charge - JC-1 or volts
resistance (units and equation)
voltage/current - ohm / VA -1
charge (units and equation)
current x time - columb / As
how to check if an equation is correct
units on the left = units on right
units must be homogenous
what is a mistake?
-measuring incorrectly
-completing an experiment incorrectly
-we can rectify our mistakes by repeating our procedures in the right way
what is an error?
-all measurements have errors
-errors are the difference between a measured value and the true value for the quantity being measured
what is a random error?
- affects precision
-cant be completely removed
-causes differences in measurements
-random errors can not be corrected - take repeated measurements and report the mean value
what is a systematic error?
-affects accuracy
-due to faults in equipment or experimental method
-causing the result to be too large/small by same amount each time.
what are the causes of systematic errors?
the time/place a measurement is taken
or
faulty measurement tools
what is accuracy?
a measure of how close the experimental values are to the known values .
closer the measurements are to the known value more accurate it is
what is precision?
a measure of how close the experimental measurements agree with each other.
what is the combination of random and systematic errors called?
measurement uncertainty
what is the interval in which the true value lies called?
uncertainty in the measurement
what is the absolute uncertainty in the mean value of measurements ?
half the range of measurements
what is fractional uncertainty?
uncertainty given as a fraction
what is percentage uncertainty?
uncertainty given as a percentage
what is the equation of percentage uncertainty?
percentage uncertainty= absolute uncertainty/ measured (mean) value x100
what do you do to the uncertainty when you add or subtract quantities in an equation?
absolute uncertainty of each value is added together
