SAT Physics
At high velocities, the kinetic energy of a moving object such as a proton
begins turning into mass
True velocity at any time during projective motion
√vx^2 + vy^2
For a charge to experience a force in a magnetic field, its velocity must ...
have a component that is perpendicular to the magnetic field lines
A wave pulse, when reflected off a fixed end, will ...
invert and return on the opposite side of the string with the same amplitude
Balanced v unbalanced forces
Balanced: Ef=0 Unbalanced: Ef=ma
Diffraction
Bending of a wave around a barrier Ex: sound waves bending around the corner of a building
Diffraction
Bending of a wave around a barrier or through an opening
Refraction
Bending of a wave due to a change in medium Speed and wavelength always change, but frequency does not change
Reflection
Bouncing a wave off of a barrier
Single slit opening with light through the slit
Bright light in center of a screen getting dimmer toward the edges of the screen
Induction
Bringing charged rod near electroscope Leaves go back to normal when it is moved away
Bohr model of the atom
Built upon the Rutherford model of the atom Said that excited, low pressure gases give off their own bright-line spectrum Said electrons only radiate energy in the form of light when they change orbits An electron can not orbit at just any radius around the nucleus, but only at certain quantized orbits Electrons can change orbits when they absorb or emit energy (if gets exactly enough energy to jump one level, jumps one level. If gets enough, can jump multiple levels. If doesn't get enough energy, ignores it) Once an electron absorbs enough energy to lift it to the highest energy level, it can escape from the atom altogether and any excess energy is converted to kinetic energy (atom is ionized) When an electron is in a higher energy level, it can jump down to a lower energy level by releasing energy in the form of a photon of light (energy of photon is equal to the difference between the energy levels the electron moves between)
Capacitance
C=q/v Q: charge on one of the plates V: voltage across the plates Proportional to A/d A: area of each plate d: distance between the plates
Heat
Can change phase or temperature
Open system
Can exchange both matter and energy with the surroundings Ex: pot of boiling water allowing water vapor to escape into the air
Closed system
Can exchange energy but not matter with the surroundings Ex: test tube with stopper in it
Isotopes
Can have different masses
Charge stored on capacitor
Capacitance x potential (V)
Double slit opening with light through the slits
Central bright band with alternating light and dark bands toward the edges of the screen Two sources of light waves Waves interfere constructively in some places (bright-antinodes) and destructively in others (dark-nodes)
Net work
Change in ke
Acceleration
Change in velocity / time
Conventional current
Charge flows from positive to negative in a circuit
Resistance-capacitance circuit
Circuit containing a battery, a resistor, and a capacitor in series
Speed of object moving in circle
Circumference/period(time for one revolution)
Line of charges, electric field is 0
Closest to smallest charge
Conductors
Conduct because they have loosely bound electrons
3 ways of transferring heat
Conduction, convection, radiation
1st law of thermodynamics
Conservation of energy in ISOLATED systems (NOT CLOSED OR OPEN) ΔU = Q - W ΔU: change in internal energy of a system Q: heat W: work that a system does WORK DONE ON A SYSTEM: W IS NEGATIVE Heat lost by one liquid gained by the other when they mix
Charge accelerating through a potential difference
Conservation of energy: 1/2 mv^2 = q(vf-vi)
Thermal conductivity
Constant Rate of heat transfer
Generator
Converts mechanical energy to electrical energy
Movement of positive charges
Current
Capacitor discharging
Current flows in opposite direction as it did with battery connected
Concave lens
DIVERGENT
Wave speed
Depends on medium
Electroscope
Device consisting of a metal ball or plate connected to a metal rod with two thin metal leaves attached at the bottom Rod and leaves insulated Study how leaves separate when a charged object is brought near Can be used to study how charges distribute themselves
Calorimeter
Device that isolates objects to measure temperature changes due to heat flow
Heat engine
Device that uses heat to perform work Three essential features: 1.) heat is supplied to the engine at a high temperature from a hot reservoir 2.) part of the input heat is used to perform work 3.) the remainder of the input heat that did not do work is exhausted into a cold reservoir, which is at a lower temperature than the hot reservoir
Magnification
Di/do
Net work
Difference between heat exhausted and heat absorbed
Theoretical max efficiency of a heat engine
Difference between temps/max temp
What happens to current if the magnet leaves the field as opposed to entering the field
Direction of current reverses
What happens to current if the magnet reverses direction
Direction of current reverses
What happens to current if the poles of the magnet moving into a loop are switched
Direction of current reverses
Second right hand rule
Direction of the force acting on the wire Fingers in direction of magnetic field, thumb in direction of current of wire, magnetic force of the wire will come out of your palm Fingers follow B, thumb follows I, palm indicates F Thumb points in direction of velocity of the charge when looking for the direction of the force acting on a charge moving through a magnetic field
Magnetic field
Directly proportional to current in wire and inversely proportional to distance from wire
Wave frequency
Directly proportional to energy
Magnetic fields current carrying wire
Directly proportional to the current and inversely proportional to the distance
Faraday
Discovered that if the flux in a loop or coil of wire changes, then a current is created and flows through the loop or coil of wire (electromagnetic induction)
JJ Thompson
Discovered the electron Said all atoms contain electrons Said atoms are naturally neutral
Superposition
Displacements of the waves that coincide at each point can be added to find the height of the wave created by constructive or destructive interference
Falling object
Distance = 1/2 g t^2
Acceleration due to gravity depends on...
Distance from the center of the earth and mass of the earth
Speed
Distance/time
Concave lenses are
Divergent
Temperature _______ during a phase change
Does not change The heat is used to change the state of the substance, not the temperature
Empty capacitor
Does not resist the flow of current and thus acts like a wire
Magnetic field lines
Drawn from the North Pole of a magnet to the south pole
Energy of a photon
E=(6.63x10^-34)f=(6.63x10^-34)(3x10^8)/λ
Binding energy
E=mc^2
Mass and energy are convertible equation
E=mc^2
Why does a prism disperse white light into the colors of the spectrum?
Each wavelength of light has a slightly different index of refraction
Specific heat
Ease with which one can raise the temperature of something The larger it is, the larger the amount of heat required to raise its temperature a certain number of degrees and the more heat is released if it cools by a certain number of degrees Does not change based on the amount of the substance Heat necessary to raise the temperature of 1 kg or 1 g of a material by 1°C of 1 K Water: 1
Electric potential
Ed
Forces in constant velocity or not moving object
Ef=0 A=0
Forces in equilibrium
Ef=0 A=0
Unbalanced forces
Ef=ma A is not 0 (object accelerates)
Electric field
Electric field lines always point in the direction a POSITIVE charge would feel a force Magnitude: E=F/q F: force Q: charge
Direction of electric field
Electric field points in the same direction as an electric force points when it is acting on a POSITIVE charge (fields point away from positive charges and toward negative)
All charges produce ______ and all moving charges produce _______
Electric fields Magnetic fields
Process used by generator?
Electromagnetic induction
Beta decay
Electron (0/-1 e) emitted
Longest ➡️ shortest wavelength: electron, proton, alpha particle
Electron, proton, alpha particle
Rutherford model of the atom
Electrons orbit around the nucleus Didn't know about energy levels
What is friction caused by?
Electrostatic force Electrons in 2 surfaces repelling each other
Alpha decay
Emits an alpha particle (4/2 He) from its nucleus
Convex lens
Enlarged virtual image when object is placed closer than focal length No image when object is at the focal length Real enlarged image when object is placed between 1 and 2 focal lengths away Reduced image if object is placed farther than 2 focal lengths away
atomic number
Equal to the number of protons in an atom of that element
Double slit interference pattern
Evidence that light has a wave characteristic The path difference for light arriving at the first maximum from two different slits is equal to one wavelength Increasing the separation between the two slits will compress the observed interference pattern Increasing the wavelength will cause the maximums displayed on the screen to spread out
Bohr's model of the hydrogen atom
Excited gases emitted a bright-lime emission spectrum When the electron makes a transition to a higher energy level, it has absorbed energy When the electron makes a transition to a lower energy level, it has emitted energy The energy levels of the electron are quantized
Centripetal force
F= (mv^2)/r R: radius of circle
Force on a current-carrying wire in a magnetic field
F=ILBsinθ I: current in wire L: length of wire in the magnetic field B: magnetic field (T) θ: angle between the length of wire and the magnetic field
Force of spring
F=kx
Newtons 2nd law
F=ma
Electric force on charge due to uniform fields
F=qE E: electric field Q: charge
Electric force
F=qe
Magnetic field
F=qvb
Force on a charge moving through a magnetic field
F=qvbsinθ Q: charge in coulombs V: velocity in m/s B: magnetic field in teslas θ: angle between the velocity and the magnetic field
Friction for accelerating object
F=uN
Line of charges, where is electric field 0?
Far from bigger charge Look at the electric field vectors, must cancel out
Converging/convex lens
Farther than twice the focal length: image reduced, inverted, real At 2f: image same size, inverted real Between f and 2f: image real, inverted, enlarged At focal length: no image Closer than focal length: virtual, enlarged, upright
Speed of sound
Fastest though densest materials
Work
Fdcosθ = ΔKE=(.5m)(vf^2-vi2) OR = ΔPE θ: angle between force and displacement If force and displacement in same direction, fd
Force on charge in uniform electric field
Fe = qe
Scalar
Has magnitude only, no direction Ex: temperature, mass, volume, time, distance
Law of entropy
Heat flows from hotter to cooler body
Phase change
Heat increases potential (NOT KINETIC) energy of a system Q=mL Q: heat M: mass L: heat of transformation
Radiation
Heat is transferred by electromagnetic waves
Heat capacity
Heat needed to raise the temperature of an object as a whole by 1°C or 1 K Q=mcΔt=mc(tf - ti) Q: heat M: mass C: specific heat Δt: change in temperature
One calorie
Heat needed to raise the temperature of one gram of water by one degree Celsius
Magnification
Hi/ho = - di/do
Positive charges naturally want to move from a point of ____ potential to ____ potential
High, low
Crest
Highest point of a wave
Δt
Horizontal distance / horizontal velocity
Heat
How much heat required to rise the liquid water from 0°C to 30° C? Heat needed = mass x specific heat x change in temperature
Index of refraction
How much light slows down in a more dense medium N=c/v N: index of refraction C: speed of light in air (3x10^8) V: speed of light in medium
Amount of voltage and current produced in a coil of wire depends on...
How quickly the magnetic field lines are crossed by the wire (faster=larger current) and number of coils (more coils=more voltage and current)
Ideal gas
Hypothetical gas whose molecules have no IMFs (intermolecular forces) Random motion No volume Elastic collisions Average kinetic energy of the gas molecules is proportional to the temperature in KELVIN At relatively low pressures and high temperatures, many gases behave in nearly ideal fashion Most gases can be treated as ideal
Acceleration is directly proportional to the electric field
If the electric field doubles, the acceleration doubles
Magnification
Image distance / object distance
Isothermal process
Internal energy change is 0
Wavelength
Inversely proportional to energy
De Broglie wavelength of a moving particle
Inversely proportional to the momentum of the particle
Acceleration due to gravity
Inversely proportional to the square of the distance from the center of the earth 1/(r^2)
Real images
Inverted Positive image distance
Converging/concave mirror
Inverted image farther away than focal point, but right size up when closer than focal point
If volume remains constant during a process...
Isochoric (P1)/(T1) = (P2)/(T2) TEMP IN K
3 types of systems
Isolated Closed Open
Isolated system
It cannot exchange energy or matter with the surroundings Ex: insulated thermos flask
How does a material become magnetic?
It is placed in a strong external magnetic field and the domains become aligned with the external magnetic field
The conversion between mechanical energy and heat energy was first developed by
Joule
Electric field
K(q/r^2) K: 9x10^9
Kelvin and Celsius equation
K= C + 273
Kinetic energy
KE=(1/2)mv^2
Heat energy
Kinetic energy of molecules that is transferred spontaneously from a warmer substance to a cooler substance
Heat
Kinetic energy of molecules transferred from a warmer substance to a cooler one
Distance between two charges where the electric field is 0
Kq/(r^2 = kq/(1-r)^2
Electric field
Kq/(r^2)
Electric potential
Kq/r
Electric field
Kq/r^2
Coulomb's law (force between 2 charges/2 charges separated by a distance)
Kq1q2/(r^2)
Electric potential energy
Kqq/r
Electric force
Kqq/r^2
An observer watching a moving object will see
Length contract in the direction of motion, it's clock slow down, and its mass increase by the equation E=mc^2
Polarized
Light vibrates in only one plane
Law of charges
Like charges repel and unlike charges attract
Vaporize
Liquid to gas
Colors
Long wavelength (low frequency) ➡️ short wavelength (high frequency) Red, orange, yellow, green, blue, violet (ROYGBV)
Sound waves are
Longitudinal
Ground state energy
Lowest energy of electrons Electrons in the orbit nearest the nucleus
Equilibrium position
Lowest point in the swing of a pendulum
Trough
Lowest point of a wave
Conservation of momentum
M1vi1 + m2vi2 = m1vf1 + m2vf2
Net force
Ma
Weight
Ma Newtons
Nucleus
Made up of positively charged protons, neutral neutrons, and negative electrons
Which fields (uniform gravity, uniform electric, uniform magnetic) cannot change the speed of the object acted upon?
Magnetic only (they cause objects to move at a constant circular speed)
Vector
Magnitude and direction Ex: force, velocity, displacement, momentum
How to solve force problems
Make forces pos/neg depending on direction
Momentum
Mass x Velocity How difficult it is to move an object from rest or to stop a moving object
Balancing two things
Mass x distance from balancing point on one side must equal the mass x distance from the balancing point on the other side
Temperature to melt
Mass x heat of fusion
Amplitude
Maximum displacement from equilibrium (angle or linear horizontal distance)
Amplitude
Maximum displacement of a wave
Entropy
Measure of the disorder or randomness of a system Greater the disorder, greater the entropy If a system is highly ordered, the entropy is low Solids have lower entropy than gas
Ammeter
Measures current Connected in series with resistor (so same current passes through ammeter and resistor) Low resistance (so they don't add to the total resistance of the circuit and thus decrease the current)
Voltmeter
Measures voltage Connected in parallel with the resistor (so the voltage will be the same across the voltmeter and the resistor) High resistance (so that current will not want to flow through them and bypass the resistor)
Weight on elevator on scale
Mg + ma
Forces on an incline - normal
Mgcosθ
Normal force on ramp
Mgcosθ
PE
Mgh
Forces in an incline - gravity parallel to surface
Mgsinθ
Friction force on ramp
Mgsinθ
Threshold frequency
Minimum energy and frequency that an incoming photon must have to be able to dig an electron out of a metal and give enough kinetic energy to the electron to escape in the photoelectric effect Minimum frequency of incoming light necessary to release an electron from a metal surface For light above the threshold frequency, a brother light means more photons, and thus more electrons released from the metal Electrons have no kinetic energy up to the threshold frequency and then their kinetic energy is proportional to the frequency of the incoming light
Elastic collision
Momentum and KE conserved
Shorter wavelengths refract _____ than longer wavelengths in glass
More
Light passing between mediums
More dense ➡️ less dense: defracted away from normal
Electric field lines
More lines for stronger charges
Electron has ______ acceleration than a proton in a uniform electric field
More, smaller mass
Parallel circuits dissipate the _____ power
Most
How to increase the amount of voltage induced in a coil
Move the magnet faster through the coil Move a stronger magnet through the coils of wire Move the magnet through more coils of wire Move more coils of wire around a magnet Move more magnets simultaneously through a coil of wire
Electromagnetic induction
Moving a magnet through a coil of wire and generating a current
Minimum speed at top of roller coaster
Mv^2/r = mg
Max speed for car turning with friction to not slip
Mv^2/r = uN = umg
Angular momentum
Mvr Mass, velocity, radius CONSERVED
Snell's Law of Refraction
N1sinθ1 = n2sinθ2 N1 and n2: indices of refraction θ1: angle of incidence θ2: angle of refraction
Pulley problems
Net acceleration of system: m1: lighter m2: heavier ((Heavy-light)g)/(heavy+light)
Pully with table
Net acceleration: ((Hanging - table mass x coefficient of friction) g)/(hanging + table mass)
Constant velocity
Net force is 0
Positively charged rod brought near knob of electroscope
Net negative charge
Neutron
No charge
Adiabatic process
No heat added or removed
Static system
No velocity and no acceleration
Mass is converted into ______ to hold the nucleus together
Nuclear binding energy So when two atoms combine, the total mass is a little less When a nucleus is split, it doesn't need all of its original binding energy anymore, so some of it is released as heat
Frequency (harmonic motion)
Number of cycles per unit time Not affected by change in amplitude, only change in length or gravity
Frequency
Number of revolutions per second
Frequency
Number of waves passing a certain point per second
Dynamic equilibrium
Object has constant velocity not equal to 0
Static equilibrium
Object has constant velocity of 0 (not moving)
Harmonic motion / vibrational motion
Object in motion follows a repeated path at regular time intervals Ex: mass on a spring, pendulum Period and frequency depend on the length of the pendulum and the acceleration due to gravity Velocity highest at equilibrium point
Newtons 1st law
Objects at rest remain at rest and objects in motion remain at constant velocity
Inelastic collision
Objects stick together Momentum conserved but KE is not
Sign of image distance
Opposite to sign of image height
Resistance
Opposition to the flow of current Electrical equivalent of friction Ohms
Momentum of a photon
P=(6.63x10^-34)/λ
Power circuits
P=IV=I^2 R = (V^2)/R P: power I: current V: voltage R: resistance
Potential energy electron
PE=qv
Conservation of energy
PEi + KEi = PEf + KEf
Uniform magnetic field
Parallel field lines (arrows)
Drawing ray diagrams
Parallel ➡️ far focal point Center of lens ➡️ keep going
Magnetic field lines
Point into south and away from north
Electric force acting on a ____ charge will _______
Positive, will match the direction of the electric field The force acting on a negative charge is opposite the field direction
Heat dissipated in circuit
Power x time
Charles Law
Pressure remains constant during a process Isobaric (V1)/(T1) = (V2)/(T2) TEMP IN K
Energy of a photon is _______ to its frequency
Proportional
Capacitance
Proportional to area/distance
Energy of a photon
Proportional to its frequency
Temperature
Proportional to the square of the average speed of each molecule
For an object in free fall, the distance fallen is ...
Proportional to the square of time
Period of pendulum
Proportional to the square root of the length of the pendulum
The width of the central antinode produced an interference pattern is
Proportional to the wavelength of the light
Adding vectors
Put tip to tail
How to melt ice and then raise the temperature of the water
Q = mLf + mcΔt
Heat absorbed or released by an object as a result of change in temperature equation
Q=mcΔt Q: heat M: mass C: specific heat Δt: change in temperature (final temperature - initial temperature) (temperature: average kinetic energy of the particles in a substance)
Photon
Quantum of light Separate bundles of light that share a wavelength, frequency, and speed Planck showed that light could be treated as tiny bundles of energy called photons Showed that the energy of a photon was proportional to its frequency
Images formed by a pinhole camera
Real, inverted
Frequency
Reciprocal of period Number of cycles/number of seconds
A lens forms an image due to the phenomenon of...
Refraction
Hooke's Law
Restoring force = -kx K:spring constant X:displacement
Frequency
Revolutions per second/min/etc
A force must be in the _____ direction as the velocity to change the velocity
Same
Astronaut throws tool
Same but opposite impulses
Parallel circuits
Same voltage Proportional current
Series v parallel circuits
Series: resistors get the same current Parallel: resistors get the same voltage
A moving object is ______ than when it is at rest
Shorter
Rutherford alpha-scattering experiment
Shot alpha particles at very thin gold foil to probe the inner structure of the atom in an experiment He expected the alpha particles to pass straight through the foil because he believed Thompson's model that the atom should not offer any resistance to the alpha particles Most of the alba particles passed through undeflected, but some went off at an angle and others bounced back off of the gold foil and completely reversed their direction Conclusions: 1.) Atom is mostly empty space since most particles passed through undeflected 2.) Atoms have a nucleus because some particles deflected at an angle and some reversed direction 3.) an atom consists of a dense, positively charged nucleus that has most of the mass of the atom. Electrons are scattered around the nucleus
A moving clock will run more _____ than a clock that is at rest
Slowly
Fusion
Small nuclei combine into larger nuclei and energy is released No radioactive products produced as a result Large amount of energy released Ex: sun
Quantum
Smallest piece of something Quantum of negative charge is the electron Light is quantized (occurs in multiples of some smallest value)
Sublimate
Solid to gas
Melt
Solid to liquid
Doppler effect
Source moving away has longer wavelengths and lower frequency
Magnetic field
Space around a magnet in which another magnet will feel a force
Projectile motion
Speed decreases on the way up and increases on the way down Net force and acceleration are down
Kelvin temp of gas doubled...
Speed of gas particles increases by √2 Average kinetic energy of particles doubles
Wavelength
Speed/frequency
Radioactive elements
Spontaneously emit particles from its nucleus because the energy of the nucleus is unstable Ex: uranium, radium, and carbon
Neutral atom
Still has charge, just equal protons and electrons
Capacitors
Store charge and electric field in a circuit E=v/d E: electric field V: volts D:distance between the plates Current eventually dies out as heat energy is lost through the resistor
Thermodynamics
Study of heat transfer
Electron
-1.6 x 10^-19C
Projectile motion
-Vertical velocity not constant (gravity) -horizontal velocity is constant -horizontal acceleration is 0 -Vertical velocity changes direction -final y velocity is the same as initial y velocity
Two weights on pulley
Sum of masses x a = WEIGHT BIG - WEIGHT SMALL
Internal energy of a substance
Sum of the potential and kinetic energies of the molecules in a substance
Period of oscillation for a spring system
T = 2 pi √m/k
Absolute zero
Temperature of 0 Kelvin All molecular motion ceases
Boyles law
Temperature remains constant during a process Isothermic P1V1 = P2V2
Refraction of light from less dense ➡️ more dense
The beam bends towards the normal
Law of conservation of angular momentum
The closer an orbiting planet is to the sun, the smaller the orbital radius and the greater the velocity
Constructive interference
The interference that occurs when two waves combine to make a wave with a larger amplitude When two waves in phase with each other meet at the same time in the same medium
Einstein's theory of special relativity
The laws of physics are the same in all inertial reference frames The speed of light is constant in all reference frames, regardless of any relative motion between an observer and a light source (everyone in any reference frame will measure the same value for the speed of light regardless of how fast he or she is moving relative to the light source)
Wavelength
The length of one complete vibration of a wave (crest to crest or trough to trough)
Which lightbulb is brightest in a circuit
The lightbulb (treat as resistor) that dissipates the most power
Two charged spheres of equal size carry a charge of +6 C and -4 C. The spheres are brought in contact and they reach an equilibrium charge. They then are separated. What is the final charge on each sphere?
The magnitude of the equilibrium charge is 6 + -4 = 2. When the spheres separate they divide the charge evenly, with each having a charge of +1 C
Why is achieving the speed of light impossible?
The object would have to have 0 length, its clock would stop, and it would have infinite mass
Which circuit will dissipate the most power?
The one with the least resistance (parallel)
Centi
10^-2
Milli
10^-3
Micro
10^-6
Nano
10^-9
Kilo
10^3
Mega
10^6
To determine the direction of a magnetic field due to the flow of electrons in a wire OR direction of magnetic force if given electron flow instead of conventional current
1st right hand rule with LEFT hand
Standing waves
2 identical waves traveling in opposite directions in the same medium at the same time create a series of nodes and antinodes Sending waves down a rope attached to a wall: the incident and reflected waves will reinforce each other in some places and cancel each other in other places. Results in a series of antinodes (loops) where constructive interference is occurring and nodes (points of no displacement between the loops) where destructive interference is occurring. Standing waves produced and water waves pass through a double slit (2 openings). The resulting semicircular wave patterns interfere with each other, creating nodes and antinodes
Nuclear fusion
2 lighter atoms (such as 2 atoms of 2/1 H) fuse to form a heavier atom (3/1 H)
Speed in circular motion
2 pi r / period
Constructive interference
2 waves occupying the same space at the same time building on each other and creating a larger amplitude wave The large wave is called an antinode Waves are in phase when they interfere constructively After the waves pass through each other, they continue moving as if they had never interfered 2 waves move toward each other on one rope and the waves are on the same side of the rope
Destructive interference
2 waves of equal amplitude approach each other on opposite sides of the rope The waves destroy each other for the instant they are occupying the same point on the rope A node (point of no displacement) is created at that point, resulting in a flat rope Waves are out of phase when they interfere destructively After the waves pass through each other, they continue moving as if they never interfered
STP (standard temperature and pressure)
273K (0°C) and 1 atm
Speed of light/electromagnetic waves
3 x 10^8 m/s
Alpha particle
4/2 He Mass: 4 Number: 2
Angle to launch at to reach max range
45°
Nuclear fission
A large atom like uranium splits into 2 smaller ones like xenon and strontium
Fission
A large nucleus splits into smaller nuclei Usually caused artificially by shooting a slow neutron at a large atom, which absorbs the neutron and splits into two smaller atoms along with the release of more neutrons and some energy
At any two points having the same height in projectile motion....
A projectile will have the same speed
Percent efficiency of a heat engine
%E = work/Qhot x 100 Qhot: amount of input heat
Universal gravitation
(Gm1m2)/(r^2) R:distance between the two centers G: 6.67x10^-11 Proportional to product of masses and inversely proportional to the square of the distance between their centers
Maximum efficiency of engine
(Max temp - min temp)/max temp KELVIN
Ideal gas law
(P1V1)/(T1) = (P2V2)/(T2) TEMP IN K
Centripetal acceleration
(V^2)/r
A/Z X
A: mass (number of protons and neutrons) Z: atomic number (number of protons) X: element
Real images
ALWAYS inverted
More dense ➡️ less dense
AWAY FROM NORMAL
Gravity field of a planet picture
All arrows point into the mass
Second law of thermodynamics
All spontaneous processes proceeding in an isolated system lead to an increase in entropy Isolated systems naturally pursue disorder Heat flows spontaneously from a substance at a higher temperature to a substance at a lower temperature and does not flow spontaneously in the reverse direction Entropy increases until a system reaches equilibrium
Entropy in isolated systems
Always increases
Current
Amount of charge moving through a conductor per second Symbol: I Amps
Lenz's Law
An induced electric current flows in a direction that opposes the charge that induced it
Law of reflection
Angle of incidence = angle of reflection as measured from a line normal (perpendicular) to the barrier
Total internal reflection
Angle of incidence is greater than critical angle Light passing through glass is reflected inside the glass
Kinetic theory of gases
Assumptions: 1.) gases are made up of particles whose volumes are negligible compared to the container volume 2) gas atoms or molecules exhibit no intermolecular attractions or repulsions 3.) gas particles are in continuous, random motion, undergoing collisions with other particles and the container walls 4.) collisions between any two gas particles are elastic, meaning that no energy is dissipated and kinetic energy is conserved 5.) the average kinetic energy of gas particles is proportional to the absolute (Kelvin) temperature of the gas, and is the same for all gases at a given temperature
The image of an object placed infinitely far away from converging convex lens...
At f
Gas
Atoms move rapidly and are far apart IMFs (intermolecular forces) are weak Expands to fill any volume Takes on shape of container Compressible Defined by pressure, volume, temperature (K), and amount of gas in moles
Isotopes
Atoms of the same element with different numbers of neutrons/different masses
Temperature
Average kinetic energy of the molecules in a substance
Horizontal motion
Ax=0 Vx = Δx/t Δx = vxt
Vertical motion
Ay = 10 Vy = viy + gt Δy = viy t + 1/2 g t^2
Linear thermal expansion
Type of heat expansion Increase in any one dimension of the solid Change in length is proportional to the original length and the change in temperature of the solid
Volume thermal expansion
Type of heat expansion Increase in the volume of the solid Change in volume is proportional to the original volume and its change in temperature
Ohm's Law
V=IR Voltage=current x resistance
Speed of a wave
V=fλ=λ/T V: speed F: frequency λ: wavelength T: period
Max height projectile
Vf^2 = vi^2 + 2(-10)Y Vfy: 0
Vf
Vi + at OR vi + gt if falling object
Vf^2
Vi^2 + 2 aΔx
Transverse waves
Vibrate in a direction perpendicular to the direction of motion of the wave Ex: the wave at sporting events
Polarization
Vibrates in only one plane Only transverse waves NOT longitudinal waves like sound
Electromagnetic waves
Vibration of an electric and magnetic field that travels though space at an extremely high speed and does not need a medium to travel through Visible light, radio waves, and microwaves
X ray v ultraviolet v visible light
Visible light has the longest wavelength and the lowest frequency X rays have the shortest wavelength and highest frequency Longest wavelength ➡️ shortest wavelength: visible light, ultraviolet, x ray
Horizontal launch
Viy = 0
Amplitude
Volume for sound and brightness for light
Work of a moving charge
W=-q(Vf-Vi)
Energy
Watts x seconds
Doppler effect
When a sound source is moving toward you, you hear a slightly higher pitch than if the sound source is at rest relative to you When a sound source is moving away from you, you hear a slightly lower pitch
Refraction
When a wave passes from one medium into another Changes wavelength and speed
Ionization
When electrons are added to or removed from an atom Negative ions: extra electrons Positive ions: deficiency of electrons
Newtons 3rd law
When objects interact, an equal and opposite force is always exerted between them
Capacitor full of charge
Will not allow current to flow and thus acts like a broken wire
Protons move ________ electric fields
With Electrons move against
Area under force x displacement graph
Work
Work energy theorem
Work and energy are transferable Ex: ball lifted gets potential energy of 100, work is also 100 because all of the work went into the potential energy
Heat added
Work done + heat exhausted
Efficiency
Work done / heat added x 100
Electric potential
Work we would have to do on a charge to move it AGAINST an electric field ΔV=work/q Aka voltage
Power
Work/time
All objects fall at same acceleration because
The ratio of weight to mass is a constant for all objects
The closer an orbiting body (satellite) gets to the planet...
The smaller the r, the faster the speed Total energy and angular momentum constant
When distance is held constant, velocity is proportional to...
The square root of acceleration
Convection
The transfer of heat by the movement of a fluid (liquid or gas) Air near floor heated, expands, becomes less dense, rises. As it rises, it cools, becomes more dense, and falls to the floor
Heisenberg Uncertainty Principle
There is a limit to the accuracy of the measurement of the speed (or momentum) and position of any subatomic particle The more accurately we measure the speed of a particular particle, the less accurately we can measure its position and vice versa WE CANNOT SIMULTANEOUSLY MEASURE THE POSITION AND SPEED (OR MOMENTUM) OF A SUBATOMIC PARTICLE WITH COMPLETE ACCURACY
Electrons and protons are placed into the same electric field...
They will both experience the same magnitude of electric force but in opposite directions The electron has less mass, so the same force will cause it to have a greater acceleration than the proton
Thomson, Rutherford, Bohr
Thomson: plum-pudding model Rutherford: planetary model Bohr: quantized energy level model
Right hand rule
Thumb in direction of current Fingers curl on side that you are looking at Way fingers point is the direction of the net magnetic field AKA Thumb along v, fingers along b, palm shows force
First right hand rule
Thumb in direction of current (I) of wire. Fingers will curl around in the direction of the magnetic field produced by that current
Waves travel faster in ____ springs than ______ springs
Tight, loose
Period
Time for a wave to vibrate once
Period (harmonic motion)
Time for one complete cycle of motion Not affected by change in amplitude, only change in length or gravity
Period
Time for one revolution
period
Time for one vibration of the wave
Half life
Time it takes for half the atoms in a radioactive sample to decay Graph: Exponential decay curve
Two plates of a capacitor
Top is positively charged Bottom is negatively charged
Charge
Total conserved
Parallel circuit
Total resistance: 1/r total = 1/R1 + 1/R2 + 1/R3 Voltage across each resistance is the same (same as the total): v total = v1 = v2 = v3 Current divides in an inverse proportion to the resistance: I1 = V1/R1 I2=V2/R2
series circuit
Total resistance=R1 + R2 + R3 Total current= total voltage / total resistance Same current passes through every resistor Current through each resistor is equal to the total current Voltage divides proportionally among the resistances according to Ohm's Law (V=IR) V1=I1R1 V2=I2R2
Conduction
Touching charged rod to electroscope Leaves do not go back to normal when it is moved away
Transfer of charge
Transfer of electrons Charge is always conserved, any charge lost by one object must be gained by another object
Mechanical wave
Transfers energy from one place to another
Heat pump
Transfers energy opposite the natural direction of natural heat flow
Resistance parallel
1/R + 1/R = 1/Rtotal
Period
1/frequency
Domain
A cluster of magnetically aligned atoms
Focal length curved mirror
Half radius
Δx
1/2(vf + vi)t OR vit + 1/2 a t^2 OR
Potential energy of a capacitor
1/2QV
Electron
0/-1 e or e- Mass: 0 Charge: -1 Location: electron orbitals around the nucleus Number in atom: atomic number
Angle of incidence air
1
Joules and calories equation
1 calorie = 4.186 joules
Two postulates of special relativity
1.) all inertial reference frames (constant velocity) are equivalent-speed of light and all laws of physics are the same 2.) all observers will measure the same value for the speed of light regardless of any relative motion between the observer and the light sources (even if light was emitted from a moving source, it would continue to have velocity of c) Object moves at speed of light, time at object slows down, object contracts in length, mass increases SPEED OF LIGHT ALWAYS ALWAYS ALWAYS C
Kepler's laws
1.) the central massive body is at one of the two foci 2.) the orbiting body moves faster when it is nearer the central body 3.) T^2 is proportional to r^3
Proton
1.6 x 10^-19C
Neutron
1/0 n Mass: 1 Charge: 0 Location: nucleus Number in atom: atomic mass - atomic number
Proton
1/1 H Mass: 1 Charge: +1 Location: nucleus Number in atom: atomic number
Δy
1/2 g t^2
Potential energy in a spring
1/2 k x^2
Planck's Constant
6.63 x 10^-34
Any two launch angles totaling _____ degrees will have the same range
90° Ex: a projectile launched at 30 degrees will have the same range as if it is launched at 60°
Velocity at max height of projectile motion
=initial horizontal velocity because the y velocity is 0 at the max height
Heat energy
Flows from hotter body to lower body
Pressure
Force / area
Ball in circle
Force and acceleration both going into the center
Coulomb's Law
Force between two charges: (Kq1q2)/(r^2) K: 9x10^9
Strong nuclear force
Force holding protons together than is greater than the repulsion between them due to like charges repelling Result of binding energy of the nucleus
Uniform circular motion
Force is perpendicular to velocity
Centripetal force
Force needed to keep object moving in circle (Mv^2)/r
Pressure
Force that the atoms exert on the walls of the container through collisions Measured in pascals/atmospheres
Restoring force
Force trying to restore pendulum to equilibrium Greatest at amplitude (acceleration also greatest at amplitude but velocity is 0) and 0 as the pendulum passes through the equilibrium position
Sound waves
Frequency: detected as pitch Amplitude: detected as volume Harmonics: detected as quality or tone (telling the difference between two voices)
Coefficient of friction
Friction force / normal force
Coefficient of friction
Frictional force/normal force
Torque
Frsin θ For equilibrium, sum of forces must be 0 and sum of torques must be 0
Impulse
F∆t = m∆v = mvf - mvi Area under force x time graph Change in momentum
Gravity formula
G (m/r^2)
Gamma decay
Gamma ray emitted Only energy changes, not atomic mass or number
Highest ➡️ lowest energies for electromagnetic waves
Gamma rays, x rays, visible light, radio waves
Longitudinal wave
Gathering up spring in a bunch then letting it go The spring vibrates in a direction parallel to the direction of motion of the wave Ex: sound
Convering convex lens object moved toward f
Gets bigger
Least amount of time to cross river
Go directly across
Harmonic motion potential energy
Greatest at the greatest displacement from equilibrium
Restoring force
Greatest when the stretch of the spring is the greatest
Amplitude
Half height of wave
photoelectric effect
The emission of electrons from a metal when light shines on the metal
Four types of radioactive decay
alpha, beta, gamma, and positron
Law of reflection
angle of I ncidence = angle of reflection
Friction for an object at rest or at constant veloci
f=forward force
Conduction
transfer of heat through direct contact