Chem/Phys Flashcards
kilo
10^3 (k)
Mega
10^6 (M)
Giga
10^9 (G)
Tera
10^12 (T)
hecto
10^2(h)
deca
10^1 (da)
Deci
10^-1 (d)
centi
10^-2 (c)
milli
10^-3 (m)
Micro
10^-6 (μ)
nano
10^-9 (n)
Pico
10^-12 (p)
horizonal projectile motion=
cos
vf and vi formula with a and change in x
vf^2=vi^2+2achange in x
newton’s laws:
- objects at rest/motion will stay at rest/motion 2. F=ma 3. equal and opposite forces
4 fundamental forces
- gravity 2. electromagnetic force (dont need to know these) 3. strong nuclear force 4. weak nuclear force
center of mass
(x1m1+x2m2+x3m3)/(m1+m2+m3)
Fstatic (the maximum it can be, but if less than max then it is opp of force applied to move the object)
(coefficient of friction)(normal force)
for gravity questions g=
m1m2/(r^2)
centripetal acceleration
v^2/r
Hooke’s law: force needed to compress/stretch a string by x is
F=kx
torque
F(d)sin() angle between force and lever arm
work=
F(d)cos() angle between force and horizontal unit=joules=1 N(m)= (kgxm^2)/s^2
mechanical advantage of ramps vs pulley
less force, same work mechanical advantage= length of incline/height of incline
power
work/time units: W=1 J/s kg⋅m2⋅s−3
for projectile motion trig
angle formed with the x axis vx=vcos() vy=vsin()
velocity
area under a velocity v time graph is displacement
acceleration
area under an acceleration v velocity graph is change in velocity
kinematics equation missing acceleration
d=(vavg)t or d=((change in v)/2)t
kinematics equation missing displacement
vf=vi+at or (change in v)=at
kinematics equation missing final velocity
(change in x)=(vi)t+1/2at^2
kinematics equation missing time
vf^2=vi^2+2a(change in x)
motion on an inclined plane
g perpendicular= gcos() g parallel=gsin()
Kinetic Energy (KE)
1/2mv^2
energy is proportional to
mass
energy and ____ are two ways of talking about the same thing
work
gravitational potential energy
mass x gravity x height or mgh
potential energy of a spring
1/2kx^2
when choosing between using kinematics or conservation of energy, remember that
time is not used in energy calculations
work
kinetic energy final-kinetic energy initial
pressure
force/area units: 1 Pa or 1 N/m^2
work
pressure (change in volume) think of the scenario in which a piston is moving in and out of a cylinder, changing the volume
if a gas doing work to expand a balloon
then the gas has to cool because it is using energy
Fahrenheit =
2(degrees Celsius) + 32
first law of thermodynamics
- Two bodies in thermal equilibrium are at the same T 1.Energy cannot be created or destroyed 2. The total entropy of a system must increase in every spontaneous reaction 3. The entropy of a pure, perfectly crystalline compound at absolute zero (0 K) is zero.
Change U=Q-W
first law of thermodynamics -the total energy change of a system is equal to the transfer of energy into the system via heat minus the work performed BY the system on its surroundings
isolated system-
no exchange of energy or matter
closed system-
no exchange of matter, only exchange of energy
open system
exchange of matter and energy
system gaining energy (heat and work)
heat into system, work by system
system losing energy
heat out of system, work on system
second law of thermodynamics
two ways of saying: 1. if two objects are in thermal contact but not in thermal equilibrium, then heat energy will flow from object with higher temp to object of lower temp 2. the entropy of an isolated system will increase over time
heat
a mechanism of energy transfer and has unites of energy
temperature
static property proportional to kinetic energy
change in volume and change in length are proportional to change in temperature
change in length= (coefficient of thermal expansion constant specific to the substance)(length)(change in temperature)
PV=
NRT
zeroth law of thermodynamics
if one system (A) is in thermal equilibrium with two other systems (B and C), then systems B and C must also be in thermal equilibrium with eachother
lowest kelvin temp possible is
0 degrees (or absolute zero)
isochoric
volume remains constant
isobaric
constant pressure
isothermal
constant temp
adiabatic
process where no heat exchange takes place
density =
mass/volume
remember mass and _____ are not the same
weight
molarity
moles/liters
density of water (need to memorize)
1000 kg/m^3 or 1 kg/L or 1 g/mL or 1 g/cm^3
specific gravity
how dense something is compared to water (bc it is a proportion it does not have units)
pressure=
force/area
pressure on an object submerged in fluid=
(density of object)(g)(depth of submersion)
absolute pressure
hydrostatic prerssure of submerged object + pressure of atmosphere
the percentage of an object that will be submerged in water is proportional to its
specific gravity
buoyant force is equal to
the weight of the fluid displaced by the object
Pascal’s Principle
The rule that when force is applied to a confined fluid, the increase in pressure is transmitted equally to all parts of the fluid. watch video
higher velocity of a fluid
the more likely it is to become turbulent
the flow rate and the pressure drop are proportional to each other
aka a large pressure drop will cause flow rate to increase
poiseulle’s law equation (describes flow of incompressible fluids through a cylinder)
know how variables relate to eachother, so if change one what the effect will be, memorize formula
Bernoulli’s Law
Law stating that pressure in a moving fluid is less when the fluid is moving faster. general ruled of ideal fluids: narrower tube->higher velocity narrower tube->lower pressure higher velocity->lower pressure
venturi effect
narrower tube-> lower pressure (venturi effect), higher velocity higher velocity->lower pressure
laminar flow
a smooth pattern of flow (opposite of turbulent)
relationship between fluid velocity and cross-sectional area of the pipe through which the fluid is travelling
v1A1=v2A2 so fluid velocity and cross-sectional area are inversely proportional
properties of ideal fluids
- the fluid is incompressible 2. the fluid is not viscose 3. the fluid exhibits laminar flow
increased flow speed resulting from being forced through a confined space results in
a zone of low pressure
scalar quantities do not have
a direction (but vector quantities do have direction)
E (magnitude of electric field)=
(kq)/r^2 or F/q The SI units of the electric field are newtons per coulomb (N/C), or volts per meter (V/m)
Work (in an electric field)
W=(kQq)/r
potential energy of a chrarge
(kQq)/r -same as work
V, electric potential
(kQ)/r
Conductivity
A material’s ability to allow heat to flow (sigma)(area/length) -sigma is a constant that is the inverse of p
Resistivity
A material’s opposition to the flow of electric current. p(length/area) -p is a constant
dimagnetic
no unpaired electrons
paramagnetic
Atom or substance containing unpaired electrons and is consequently attracted by a magnetic field
magnetic fields cannot be blocked
but, it can be rerouted with a material that conducts better than the materials around it, ie copper
electric field lines are drawn
from positive to neg charges
an insulator does not have free electrons, but when a charged object is brought near it…
polarization does occur at an atomic level
electric potential energy=
electric potential (charge)
electric potential=
k(Q/r)
1atm
ERROR!
direction a current moves is
opposite that of the actual flow of electrons
voltage
(current)(resistance) V=IR The unit is Volt (V) which is also equal to Joule per Coulomb (J/C) The SI unit of electric current is the ampere The unit of resistance is the ohm
power=
current x voltage P=IV
Kirchoffs laws
- In accordance with the conservation of electric charge, the sum of currents entering a junction must equal the sum of currents exiting the junction 2. The sum of the voltage sources in a circuit loop is equal to the sum of voltage drops along that loop.
Resistors in parallel
1/R=1/R₁+1/R₂+1/R₃+…
Resistors in series
R=R₁+R₂+R₃+…
C (capacitance)
Q/V charge/voltage which means there are two ways to increase the charge in a capacitor 1. to increase the voltage, because a greater potential difference will drive the accumulation of more charge 2. to increase the capacitance, which is a measure of how well the capacitor itself, as a device, can store charge
Capacitor
a device used to store an electric charge, consisting of two parallel plates takeaway for MCAT C (capacitance) =(constant)(A/d) (assumption is that this all occurs in a vacuum-but if there is something between the plates then multiply by the ratio of the constant for the substance/constant for vacuum) aka increasing the area of the plates and bringing them closer together will increase the capacitance
electric field arrow lines go from
positive to negative charge
E (strength of an electric field)=
V/d (voltage difference/distance between the plates) *can only use this formula with uniform electric fields
potential energy from a capacitor
PE=1/2CV^2
Capacitors in Series
1/C=1/C₁+1/C₂+…
Capacitors in Parallel
C=C₁+C₂+C₃+…
magnetic fields only affect ______ charges
moving (unlike electric fields)
magnetic field generated by current moving through a wire
B=(constant)(current)/(2)(pi)(distance from the wire) B=(mu)(I)/(2)(pi)(r)
right hand rule for current-carrying wires
place thumb in direction of the current running through the wire (I), the direction of the magnetic field follows the pattern in which your fingers curve
force exerted by a magnetic field on a moving particle=
F= qvBsin() v=velocity q=charge ()=angle of the velocity of the particle to the magnetic field (force will be maximized when the motion is perpendicular) -applied to positive particles only
force exerted by a magnetic field on a current-carrying wire=
F=(current)(length)(strength of magnetic force)sin()
Lorentz force
sum of the electrostatic and magnetic forces acting on a body
capacitance _______ as the distance between parallel plates decreases
increases
When a dielectric material is introduced between the plates of a parallel-plate capacitor and completely fills the space, the capacitance
increases
periodic motion
any motion that repeats in a regular cycle
potential energy for periodic motion
pendulum: mgh mass on an ideal spring: 1/2kx^2
Hooke’s Law
F=-kx (restoring force)
Period of a Spring
Ts (period of a spring) = 2π√(m/k)
Period of a pendulum
Tp=2π√l/g
large value of T (period) means a ______ frequency
low
Velocity of a wave
v = fλ
The speed of sound depends on
the compresibility (represented by the bulk modulus variable) travels slowest through gases bc they are the most compressible travels fastest through rigid, incompressible solids
Higher amplitude means
more energy
in a standing wave the points of zero displacement are called _____ and the points of maximum displacement are referred to as _______
zero displacement=nodes maximum displacement=antinodes
fundamental frequency
first harmonic
standing wave on a pipe vs standing wave on a taught string
pipe: ends on an antinode on one end and node on the other end taught string: ends on a node at both ends
standing wave in a pipe
can only work for odd values of n
speed of sound in air
343 m/s
Intensity of a wave
power/area (W/m^2)
period and frequency are
inversely related
Critical damping
the condition in which the damping of an oscillator causes it to return as quickly as possible to its equilibrium position (rest position)
Underdamping
damping in a system that experiences a small resistive force, so that the system oscillates with decreasing amplitude, slowly decreases to zero
Overdamping
Heavy damping such that the system takes longer to return to equilibrium than a critically damped system, but returns to rest faster than underdamping
viscous damping
is caused by such energy losses as occur in liquid lubrication between moving parts or in a fluid forced through a small opening
beat frequency
f=|f₁-f₂| beats are caused by the interference of two waves at the same point in space
wave-particle duality
light can behave as both a wave and a particle
light is an
electromagnetic wave
speed of light (c)
3.00 x 10^8 m/s (fastest speed possible for all forms of conventional matter in the universe) all electromagnetic waves travel at the speed of light
Velocity of a wave
v = fλ
Energy of a wave
hf (h is planck’s constant) or hc/wavelength
high energy waves
high frequency, short wavelength
low energy waves
low frequency, long wavelength
spectrometer
generates a spectrum, used to determine the degree to which a substance, often in solution, absorbs different wavelengths of light
apparent color of an object
is caused by the wavelengths of light that dont absorb, aka an absorbance peak for a wavelength means that the substance will NOT appear to be that color
reflection and refraction
both occur when the wave encounters a different medium than the on it is travelling in, diffraction=changes path, reflection=bounces off the new medium
Circumference of a circle
2πr
Area of a circle
A=πr²
SI base units
mass-kg, length-m, time-s, temp-K, amount of substance-mol, electrical current- A (ampere), luminous intensity - candela (cd)
scalar quantity
A quantity in physics, such as mass, volume, distance, speed and time, that can be completely specified by its magnitude, and has no direction. Distance, along with speed, is a scalar quantity, meaning that it measures only magnitude and not direction. Since the car continues to move throughout the process, distance is constantly increasing and is never negative.
when you take the square root of a decimal
it becomes a slightly larger decimal
mechanical energy
KE + PE is lost/not conserved when there is friction or air resistance
conservative force
A force, such as gravity, that performs work over a distance that is independent of the path taken. Gravity and the spring force are classic examples of conservative forces, or forces that do work that does not depend on the path taken. Conservative forces can also be thought of as those that act in situations where mechanical energy is conserved.
nonconservative forces
Forces that its work depends on the path. Eg: friction. Both air resistance and friction are nonconservative forces. If they are present during a scenario, mechanical energy will not be conserved.
One joule is equivalent to
one N∙m
one newton is the same as one ____
(kg∙m)/s^2
Watts are the unit for….. and are equivalent to…..
power (kg∙m2)/s3
efficiency
(useful work) / (energy in)
laws of thermodynamics
The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases. The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero
work (dealing with pressure)=
PΔV
A hoop and a sphere, each of mass M, are rolled down a frictionless ramp. At the bottom of the ramp, which object will have the greater translational velocity, and why?
An object’s moment of inertia contributes to its rotational kinetic energy. Since a higher moment of inertia correlates to a higher rotational KE, it also means that translational KE must be lower, as the sum of these two values must equal the potential energy at the top of the incline. For the sphere, more of its mass is concentrated towards the center than for the hoop. As a result, the sphere’s moment of inertia will be lower.
If a gas is expanding in a container, then ____________.
it is performing work on a container -it also loses heat because it is performing work, so it gets colder even though it gets bigger (when a gas is compressed, work is being done on it)
work-energy theorem
whenever work is done, energy changes aka work and energy are the same, work done=energy
adabiatic
no heat or matter is added to the system/transferred
Isobaric
constant pressure
isothermic
constant temperature
isochoric
constant volume
Zeroth Law of Thermodynamics
If two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other.
First law of thermodynamics
Energy can neither be created not destroyed but it may be converted from one form to another
second law of thermodynamics
Every energy transfer or transformation increases the entropy of the universe.
Third Law of Thermodynamics
No system can reach absolute zero, so can never have anything below 0 degrees kelvin
Newton’s First Law
An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
Newton’s Second Law
F=ma
Newton’s Third Law
For every action there is an equal and opposite reaction
Watts (units of power)
Joules/second
frequency of oscillation
f = 1/2π [√(k/m)]
Period of oscillation
inverse of frequency of oscillation
Convex v Concave meniscus
concave-when interacts with the walls of the container more strongly than it does with itself convex- when it interacts with itself more strongly than it does with the container
scalar quantity
a quantity that can be described by magnitude only and has no direction
units for electric potential
Volts or J/C (joules/coulomb)
units for electric field
N/C or V/m
charge has units of
coulombs
electrostatic force has units of
newtons (like all forces)
Period of a pendulum
T=2π√l/g
elastic potential energy of a spring
U = ½ kx^2
1 atm is equal to
101,500 Pa
how do voltage and current go through parallel resistors
Voltage drops across parallel branches of a circuit are always identical; this idea forms the basis for Kirchoff’s second law. However, if the resistance values of the resistors are not equal, different amounts of current will pass through them. Specifically, more current will travel through the branch of lower resistance.
of molecules in a mol
6 × 10^23 molecules
charge of an ion
1.6 × 10-19 C/ion
Capacitance
the ability of a conductor to store energy in the form of electrically separated charges C = εA/d
a particle must have what to experience the effect of a magnetic field
it is evident that a particle must possess both velocity and a charge (whether positive or negative) to be affected by a magnetic field F=qvB
Lentz’s Law
Direction of the induced current is such that the induced magnetic field always opposes the change ex. This law, which brings to mind conservation of energy and even Le Châtelier’s principle, states that a change to a magnetic field will always generate a current that counteracts that change. Here, the external field is becoming stronger, or more heavily positioned out of the page. To resist this change, it will induce a current that promotes a field pointing the opposite direction, into the page. The right-hand rule tells us that this current must travel clockwise.
right hand rule for magnetic force
this is for positive charge, so if negative then flip
what does not change when a wave goes from one media to another (and the two media have different densities)
frequency
the decible scale is a logarithmic scale in which each 10 decibel interval, or a factor of 10, thus a 40 dB difference represents a _______ difference in intensity
10^4 or 10000
total internal reflection occurs only when traveling from a material with a _______ refractive index to a material with a ________ refractive index
higher, lower
convex mirrors have _____ focal lengths
negative
convex mirrors always form ______ images
virtual
Magnification equation
m = -i/o (negative because the image is inverted)