Physics Flashcards
What is a law or principle?
A statement that describes a natural phenomenon
What is a theory?
Reasonable explanation of series of observed phenomenon
Fundamental quantity for length
Meter
Fundamental quantity for mass
Kilogram
Fundamental quantity for time
second
Fundamental quantity for temp
Kelvin
Fundamental quantity for electric current
Ampere
Fundamental quantity for luminous intensity
Candela
Fundamental quantity for molecular quantity/amount of substance
mole
Which of the fundamental quantities gets it’s basis from a block of platinum
Kilogram
What is a derived quantity?
Quantities formed from the 7 fundamental quantities`
Unit for force
Newton
Unit for work and energy
Joule
Electric Field
Newton per coulomb
Atomic Number is equal to
The number of protons
Avogadro’s number
6.02x10^23
What is an isotope?
Different number of neutrons
Accuracy
closeness to the actual value
Precision
closeness of measurements to each other
Instantaneous speed
d2-d1/t2-t1
Average velocity
xf-xi/tf-ti
with direction
xf>xi +
xf
Instantaneous acceleration
v2-v1/t2-t1
Looking for vf without distance (x)
Vf= Vo + at
Looking for vf with distance (x)
Vf^2= Vo^2 + 2a(Xf-Xo)
Looking for Xf with Vf without a
Xf= Xo + 1/2(Vf-Vo)t
Looking for Xf with a without Vf
Xf= Xo + Vot +1/2at^2
Describe velocity in freefall
Vi=Vf=Vmax
What is the velocity at Xmax in free fall?
O
What is acceleration in free fall?
gravity
Velocity along the x of projectile motion
constant
Velocity along the y in projectile
constantly changing
A along the y in projectile
constant (g)
Horizontal acceleration in projectile
0
Time of flight for projective
T1=T2
Law of inertia
Fnet=0
Inertia
Resistance to any change in state of motion
Measure of object’s inertia
Mass
Law of acceleration
F=ma
Most common force
Gravity
Force of gravitational attraction on an object
F(g)=mg=w
Force definition
push or pull
vector quantity
Law of action and reaction
Forces occur in pairs (equal but opposite force)
Fab=-Fba
3 Contact force
Normal, Tension, Friction
Normal force
perpendicular support force of a surface on an object
Tension
Pulling force on a hanging object
Friction
resistive force between two surfaces that are in contact or that move relative to each other
Equation for friction
f=uN
Two types of friction
Static (at rest)
Kinetic (in motion)
Kepler’s Laws of Planetary Motion
- law of orbits
- Law of areas
- Law of periods
Newton’s Universal Law of Gravitation
Fg=Gx M1M2/r^2
Universal Gravitational constant (G)
G= 6.67 x10^-11
Acceleration due to gravity of a planet
g= G(Mplanet)(r^2planet)
Uniform circular motion definiton
Acceleration due to change in velocity in terms of direction
Centripital acceleration
a©= v^2/r
Centripital force
F©= mv^2/r
Direction of centripital force and acceleration
always toward the centre of circular path
Orbital Speed
v= /GM/D
Work definition
Product of force on the object and displacement parellel to the force
Scalar
Work equation
W= Fd W= Fdcos(theta)
Types of work
positive= f and d are parallel
negative work= f and d are anti parallel
no work= f is 0, d is 0, or f and d are perpendicular
Unit of work
Joule
Newton Meter
Power definition
Rate of doing work
Power equation
Pave= W/t
Unit of power
Watt
Joules/second
Kinetic energy equation
KE= 1/2mv^2
Potential Energy definition
Energy by virtue of position
PE equation
PE= mgy
Types of potential energy
GPE
EPE
GPE Equation
GPE= mgh
EPE Equation
U= 1/2 kx^2
k is spring constant
x is displacement from rest position
Total mechanical energy equation
TME= KE + PE
Work-energy theorem defintion
change in energy of a system means work was done
Work (energy) equation
Wtotal= delta ME= delta PE + delta KE
Conservation of energy
delta KE= delta -U
Conservation of Mechanical energy
TME of isolated system remains unchanged
delta TME= 0
TMEi=TMEf
Momentum defintion
Quantity of motion
Momentum equation
p= mv
follows the direction of v
vector quantity
Impulse definition
change in momentum
Impulse equation
delta p= m(delta v)
J= Fave(delta t)
Force in terms of momentum
rate of change of momentum
F= (delta p)/(delta t)
Unit for impulse
N/sec or Kgm/sec
Conservation of momentum
linear momentum of system is constant
pi=pf
Collision def
strong interactions between bodies that last a relatively short time
TYPES OF COLLISIONS
Elastic- linear momentum and KE is conserved
Non elastic- Linear momentum is conserved
decrease in KE after collision. Completely ineleastic when 2 bodies stick together and move as one
Rotational motion def
1 position but rotating
Torque def
Rotational equivalent of force
tendency of a farce to make a body rotate
Torque equation
t= Fl t= Fl(sin theta)
Centre of gravity def
Point where weight of object is concentrated
Centre of gravity ___ centre of mass
equal if acceleration due to gravity is the same throughout the body
Where is the centre of gravity located
in the geometric centre for symmetrical bodies
Conditions of equilibrium
- translational equilibrium
- rotational equilibrium
- mechanical equilibrium
Translational equilibrium
summation F= 0
object does not accelerate
Rotational equilibrium
summation t= 0
clockwise= ____ torque
counter clockwise= ____ torque
negative; positive
Fluids def
anything that has the capacity to flow
Density of homogenous fluid (p) equation
mass per unit volume
p= m/v
Specific gravity (SG)
ratio of density of substance to density of water
relative density
SG= p(obj)/p(water)
Hydrostatic pressure equation (Pfluid)
Pfluid= pgh
Centre of Mss Equation
Xcog= summation (miXi)/ summation (mi)
Hydrostatic pressure units
Pascal
1 N/m^2
Pascal’s Principle def
Pressure applied to enclosed fluid is transmitted undiminished to every point in the fluid and to the walls of the container
Pascal’s Principle equation
F1/A1= F2/A2
Archimede’s Principle def
A body submereged in fluid is buoyed up by a force equal to weight of the displaced fluid
Archimedes principle equation
Fb= dgV
Fb (Buoyant force) = W displaced liquid
Principle of continuity equation
A1V1=A2V2
A= cross-sectional area of pipe
Bernuolli’s Equation
P1+dgh1+1/2dv1^2= P2+dgh2+1/2dv^2
P=pressure
h= height
Temperature definition
ave KE of particles in a substance
C to K
Tk= Tc + 273
K to C
Tc= Tk - 273
C to F
Tf= 9/5Tc +32
F to C
Tc= 5/9(Tf-32)
Heat (Q) def
energy transferred due to temperature difference
hot to cold
Heat units
Kcal
amount of heat needed to raise 1 kg of water 1 degree celcius
Heat Capacity ( C) def
amount of energy needed to raise temp of a body 1 degree celcius
Heat Capacity ( C) equation
C= delta Q/ delta T
Specific Heat ( c) def
the amount of heat needed to change the temp of a unit of mass of substance by 1C
Specific heat ( c) equation
c= Q/m(deta T) c= C/m
Change of temp equation
Q=mC(delta T)
Change of state equation
Q=mL
L is latent heat
Factors affecting change of state
pressure
dissolved substances increase BP if non volatile
Expansion equation
delta L= (alpha)(delta T) —>aAT
proportional to change in temp
Conservation of heat equation
in a closed system, heal lost by one body is equal to heat gained by other body
Qlost=Qgained
Zeroth law of thermodynamics
if 2 systems in insulation are in thermal equilibrium with a 3rd system then the 2 systems are in thermal equilibrium with each other
First law of thermodynamics
total energy change of a closed system is equal to the heat transferred to the system minus work done by the system
Delta U= Q- W
Thermodynamic processes
- Adiabatic= no heat transfer (Q=0)
- Isochoric= constant volume process; system does no work to surroundings (W=0)
- Isobaric= constant pressure process; work done by expanding gas (W=P(delta V)
- isothermal= constant temp process
Second law of thermodynamics
no conversion of heat to mechanical energy is 100% efficient
heat flows from hot to cold
HEAT ENGINE EQUATION
W= Qh- Qc
W is mechanical work
h hot
c cold
Thermal efficiency of an engine equation
e= W/Qh e= 1- (Qc/Qh)
Ideal efficiency (eideal)
eideal= 1- (Tc/Th)
Conservation of charge
total amount of charge of an isolated system remains constant
all substances are normally electrically neutral
Coulomb’s law (FE)
FE= k(q1q2/r^2)
FE is electrostatic force
k is 9.0 x10^9 Nm^2
Electrostatic constant (k)
k is 9.0 x10^9 Nm^2
Direction
x= i hut y= j hut z= k hut
Unit of electron charge
coulomb
Electric field def
force per unit of charge
Electric field (E) equation
E= FE/qo
FE is electric field
qo is test charge
Unit of Electric field
Newton per coulomb
positive vs negative elctric field
Positive has electric field
negative accepts electric field
Electrostatic Potential Energy def
Energy of a charge by virtue of position in electric field
In a uniform electric field PEe is the work done by the electric field
Electrostatic Potential energy (PEe) equation
Product of force magnitude and component displacement in the direction of force
PEe= qoEd
E is magnitude of electric field
d- displacement of test chrge
Unit of Electrostatic potential enegrgy
electronvolt (eV)
Electric potential def
electric potential energy per unit of charge
Electric Potential (V) equation
V=Ed
Potential difference (Vab)
work that must be done to move a unit charge slowly from one point to another against electric force
Electric current def
amount of charge passing through a given point per unit of time
Electric current (I) equation
I= q/t
Electric current unit
Ampere=coulomb per sec
Ohm’s Law def
Relates voltage, current and resistance
potential difference or voltage in a conductor is directly proportional to the current in the conductor
Ohm’s Law equation
V= IR
Unit of voltage
volt
Unit of current
Ampere
Unit of resistance
Ohm
Simple resistor circuit (I) equation
I= V/(Re+Ri)
Re is ext resistance of the cell
Ri is int resistance of cell
n Resistors in series equation
Vtotal= add all V or add all IR Itotal= add all I Rtotal= add all R
n resistors in parallel
1/Rtotal= 1/R1 + 1/R2 etc
Resistance of a length wire ( R) equation
R= p(l/A)
p isresistivity of wire
l is length
A is cross sectional area
unit of conductance
mhos
Junction rule
algebraic sum of the currents (I) into any junction is 0
Loop rule
algebraic sum of the potential difference (V) in any loop must equal 0
Electrical work (W) equation
W= VIt
Electrical Power ( P) equation
P= VI= I^2R= V^2/R
Capacitance def
measure of the ability of capacitor to store energy (PE)
dependent on geometry and insulator
ratio of charge to potential difference
not dependent on charge and voltage
Unit of capacitance
farad=coulomb/volt
Capacitance ( C) equation
C= Q/Vab
Q is total charge
Vab is voltage
Parallel plate capacitor equation
C= EA/d
A is area of plate
Eo is constant
d is distance
Capacitors in series equation
1/Cef= 1/C1 + 1/C2 +….
Capacitors in parallel
Cef= C1 + C2 +….
Magnetic force definition
a charge moving in uniform magnetic field
Magnetic force (FM) equation
FM= qvBsin(theta)
B is magnetic field
F= qv x B
right hand rule for direction of FM
Lines of induction def
external to a magnet, lines of B leave north pole of magnet and enter south pole of a magnet
Units of magnetic field (B)
tesla= N/Am
Magnetic properties of matter
- Paramagnetism (feebly attracted by a strong magnet)
- Ferromagnetism (strongly attracted by a magnet)
- Diamagnetism (freely repelled by a strong magnet)
Motional EMF equation
y=vlBsin(theta)
y is electromotive force
Magnetic flux equation
o= BAcos(theta)
o is magnetic flux
B is magetic flux density
A is area of loop
Faraday’s law equation
electromotive force in a conductor is equal to the rate of change of the magnetic flux
yi= -delta o/ delta t
Lenz’s law def
emf and induced current are in a direction that tends to opposed the change that produced them
transformer wires
primary carries input power
secondary
Transformer Voltage of secondary coil equation
V2= (N2/N1) V1 N1I1= N2I2
Oscillatory Motion def
backa nd forth motion along the same path
Hooke’s Law equation (restoring force)
Fr= -ks
Fr is restoring force
k is constant
s is elongation or compression
Period of oscillating spring (Ts) equation
Ts=2π√m/k
Ts is period of spring
m is mass
Period of simple pendulum equation (Tp)
Tp=2π√l/g
l is length of string
g is gravity
Frequency of oscillation (f) equation
f= 1/T
reciprocal of period
w=2πf
Waves def
transport of energy through a medium by the motion or change in the medium
transport of energy and momentum from one point in a medium space to another without transport of matter
kind of waves
- mechanical - require a medium
- electromagnetic - does not require medium
- transverse - direction of wave motion is perpendicular to the direction of wave propagation
- Longitudinal waves - direction of wave motion is parallel to direction of wave propagation
Wave charac
- Wave pulse
- wave train
- Harmonic wave
- wavefronts
- crest
- trough
- amplitude A
- wavelength λ
- period T
- frequency f
- wave velocity v
- relationships between v, f, λ, t
Relationship between wavelength, period, frequency, and wave velocity
v= λf = λT where f = 1/T
Wave pulse
single disturbance or distortion of shape of medium from normal
Wave train
series of wave pulses
Harmonic wave
sinusoidal wave train that propagates down a string
Wavefronts
curves of constant phase for 2D waves
Crest
highest point in wave
Trough
lowest point in a wave
Amplitude
max displacement form equilibrium position
wavelength
distance between 2 consecutive identical points in a wave
Period
time for 1 complete wave to pass a given point
frequency
number of waves that pass a given point per second
wave velocity
distance through which wave moves per second
Properties of waves
- Reflection - bouncing of wave due to barrier
- Refraction - bending of wave due to change in medium
- Diffraction - bending of wave due to an opening
- Interference - meeting or overlapping of waves
- Dispersion - changing in shape of wave gradually spreading out
- resonance - increase in amplitude of a system when it oscillates due to a series of impulses that matches the natural frequency of the system
types of interference
constructive - waves are n phase
destructive - waves are out of phase
Doppler effect
apparent change in frequency of waves due to relative motion between observer and source of waves
Water waves
combination of longitudinal and transverse characteristics
particles trace circular or elliptical orbit as it moves along the wave
wavelength is equal to the distance between two consecutive arcs
Sound waves
longitudinal wave
frequencies of sound waves
- audible range = 20Hz< f < 20 x10^4 Hz
- Infrasonic = f < 20x10^4 Hz
- ultrasonic = f > 20x10^4Hz
Sound intensity def
energy transported over an area per unit of time
Sound Intensity (I) equation
I = E/At
Unit of Sound intensity
J/m^2s= W/m^2
Sound intensity level (β) equation
β= 10db log (I/Io)
Io is equal to 10^-12
Speed of electromagnetic wave
3 x 10^8
Polarization def
wave property that describes the orientation of the electric field vector of an EM wave
Speed of light
2.9979 x 10^8 m/sec
