Mr prince Flashcards
what does “terra” equate to
T - 10^12 - a thousand billion (trillion)
what does “giga” equate to
G - 10^9 - a billion
what does “mega” equate to
M - 10^6 - a million
what does “kilo” equate to
K - 10^3 - a thousand
what does “milli” equate to
m - 10^-3 - a thousandth
what does “nano” equate to
n - 10^-9 - a billionth
what does “micro” equate to
u - 10^-6 - a millionth
what does a “pico” equate to
p - 10^-12 - a thousand billionth (a trillionth)
what does a “femto” equate to
that’s just getting ridiculous
how do you convert mm^2 into m^2
divide by a million
how to convert m^2 into mm^2 !
multiply by a million
what are the base units
time (s) , length (m) , mass (kg) , temperature (Kelvin) , amount of substance (moles), current (amps), luminous intensity (candela)
what are the base units of force
kgms^2
what are the base units of work done (energy transferred)
kgm^ 2s^-2
what is a Systematic error
an error with equipment used - occur in one direction and can be accounted for
what is a random error
human error in taking readings / environmental variations - in either plus or minus directions
how do you estimate uncertainty of results
+/- half the range of repeats (half the difference between highest and lowest result in multiple recordings of the same experiment)
what is a measuring equipment’s “resolution”
the smallest measuring interval of uncertainty in a single reading
how do you find uncertainty in a measuring equipment
half the resolution of the equipment
what is absolute uncertainty
and estimated value of uncertainty accounting for all errors and uncertainties (basically just uncertainty)
how to calculate percentage uncertainty
absolute uncertainty
——————————– x 100
actual results
what is an “accurate” measurement result
if the result is judged close to the true value
what is a “precise” measurement result
the values gathered by repeat experiment are very close even if inaccurate
how to compound (combine) uncertainties
Step 1 - convert all absolute uncertainties to percentage uncertainties
Step 2 - add the percentage uncertainties
Step 3 - convert back to absolute uncertainty (by multiplying by the actual result)
how to compound powered uncertainties
Step 1 - convert to percentage uncertainties
Step 2 - multiply by the power to the percentage uncertainty (e.g if squared multiply by 2)
Step 3 - convert back into absolute uncertainty
what are the 4 SUVAT equations of motion
final velocity (v) = initial (u) + acceleration (a) x time (t)
distance travelled (s) = ut + 1/2at^2
V^2 = u^2 + 2as
s = 1/2 x (u+v) x t
what is speed defined as
the rate of change of distance
what is velocity defined as
the rate of change of displacement
what is acceleration defined as
the rate of change of velocity
what is the equation for velocity
change in distance
—————————- = velocity
change in time
What are dynamics
A section of mechanics looking at the motion of bodies under forces
What are the three efficiency equations
Efficiency = useful energy out / useful energy in
Efficiency = useful work done output / work done input
Efficiency = useful power output / total power input
How can can object be stable
It needs a low centre of gravity
A wide base
What happens when an object is in stable equilibrium
An object will fall back to its original position
What happens when an object is in an unstable equilibrium
It will continue to fall away from its original position
What happens when an object reaches a neutral equilibrium
It remains in equilibrium in its new position
What is the moment
A moment is the turning effect about a particular fulcrum or pivot
What is the moment defined as
The fore multiplied by the perpendicular distance of the line of action of the force to the pivot
What does it take for an object to be in equilibrium
The sum of clockwise moments is equal to the sum of anticlockwise moments
