1. now from the top, make it drop, that's some WAAP [COMPLETE] Flashcards
working as a physicist
Define speed
rate of change of distance
define velocity
rate of change of displacement
define distance
distance refers to how much ground an object has covered during its motion
define displacement
displacement refers to how far out of place an object is and is the overall change in the objects position
base unit of mass
kilogram - kg
base unit of length
metre - m
base unit of time
seconds - s
base unit of temperature
kelvin - k
base unit of electrical current
ampere - A
base unit of amount of substance
moles - mol
T
tera - 10^12
G
giga - 10^9
M
mega - 10^6
k
kilo - 10^3
d
deci - 10^-1
c
centi - 10^-2
m
milli - 10^-3
µ
micro - 10^-6
n
nano - 10^-9
p
pico - 10^-12
Derive Hz
Frequency = 1/time
f=1/t
f=1/s=s^-1
Derive Pa (pascal)
pressure = force/area
p=F/A
p=ma/A
p=kg m s^-2/m^2
p=kg m^-1 s^-2
Derive J (joule)
work done = forcedistance
W=fd
W=mad
W=kg m s^-2 m
W=kg m^2 s^-2
——————————————————————-
Kinetic energy = 1/2mass*velocity^2
E=0.5mv^2
E= kg (m s^-1)^2
E= kg m^2 s^-2
what are homogenous equations
units on both sides of the equation are equal
prove that v^2 = u^2 +2as is homogenous
v^2
=(ms^-1)^2
=m^2 s^-2
—————————————————————-
u^2 + 2as
=(ms^-1)^2 + ms^-2 m
=m^2 s^-2 + m^2 s^-2
=m^2 s^-2
What is accuracy
accuracy is how close to the real value
What is precision
precision is how close the results are together
What are random errors
random errors are unpredictable and occurs by chance
How do random errors typically affect a graph
random errors typically affect the gradient of the graph
how to reduce the effect of random errors
to reduce the effect of random errors, take multiple measurements
What are systematic errors
Systematic errors happens consistently and will affect all measurements by the same amount
how do systematic errors affect a graph
systematic errors will not affect the gradient of the graph but will displace the line
examples of systematic errors
-zero error
-parallax
what is the absolute uncertainty of a DATA SET
half the range of the data set
What is the absolute uncertainty of a device
the absolute uncertainty is the smallest scale reading of that instrument
how to work out percentage uncertainty
percentage uncertainty
(absolute uncertainty/value)*100
what uncertainty to use when data is added or subtracted
add absolute uncertainty
what uncertainty to use when data is multiplied or divided
add percentage uncertainties
What to do with the uncertainty when data is raised to the power of n
Multiply the percentage uncertainty by the power
What does the error bar on the graph tell us
the error bar shows the absolute uncertainty
How to draw the line of worst acceptable fit
draw a line from the bottom of the first error bar and the top of the last error bar or vice versa
how to work out percentage uncertainty in the gradient
percentage uncertainty of gradient
[ (best gradient-worst gradient)/best gradient ] * 100
derive N (newton)
force (N) = mass (kg) * acceleration (ms^-2)
=kg m s^-2
derive W (watt)
power (W) =work (or energy) (J) / time (s)
=J s^-1
———————————————————–
J = N * m
J = kg * m * s^-2 * m
J = kg m^2 s^-2
———————————————————–
W = kg m^2 s^-2 s^-1
=kg m^2 s^-3
derive C (coulomb)
charge (C) = current (I) * time (s)
=As
derive V (volt)
potential difference (V) = energy (J) / charge (C)
=kg m^2 s^-2 / As
=kg m^2 A^-1 s^-3
derive Ω (ohm)
resistance (Ω) = p.d. (V) / I (A)
=kg m^2 A^-1 s^-3 / A
=kg m^2 A^-2 s^-3
