Final Cheat Sheet - Summary Survey of Physical Science PDF

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Final cheat sheet for Jeremy Redd...

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TEST 1 Scientific Method – Hypothesis: Educated prediction of behavior that an experiment can be performed to verify. – Theory: Mathematics or logic that comes from verified repeatable experiments. – Law: Set of mathematical principals describing nature that have been verified to such an extent as to be unquestioned in science – Model: The actual mathematical description of the behavior of some system. Six “Self-Evident Truths” – Existence – Causality – Position Symmetry – Time Symmetry – Principle of Noncontradiction – Occam’s Razor Fundamental Forces Gravity Electromagnetic Strong Nuclear Weak Nuclear Motion – First accurate description devised by Galileo. – Building upon the work of Galileo, Newton developed complete descriptions based on three laws. Velocity -Units of distance per time. -Unlike speed has information about direction. -Velocity simply adds if velocity adds and adds with Pythagorean theorem if velocities are in different directions. Acceleration -Defined as change in velocity per change in time. -Units of distance per time squared. Mass -Also known as inertia -Mass is a measure of an objects resistance to a change in its velocity. -A very massive object is hard to accelerate; a low mass object is relatively easier to accelerate.-Also known as inertia -Mass is a measure of an objects resistance to a

change in its velocity.-A very massive object is hard to accelerate, a low mass object is relatively easier to accelerate. Weight is NOT mass. – Weight is the force due to the gravitational interaction, and is directly proportional to mass. – W=mg – Acceleration of gravity is g: g=9.8 m/s^2 Newtons Laws Newtons First Law – Also known as law of inertia – An object in uniform motion stays in uniform motion unless acted upon by a force Newtons Second Law – F=ma Newtons Third Law – Any force that acts between two bodies acts on both bodies with equal magnitudes but in opposite directions.– Mathematically: F1on2=-F2on1 The Gravitational Interaction – W=mg when one is close to a large gravitating body. -This means that near a gravitating body that acceleration is constant. – Far from a gravitating body F=GmM/d2 -This means that if distance is doubled, the force decreases by a factor of 4. If mass is doubled then force is doubled. General Relativity -Proposed by Einstein in 1915. -It states that objects move not in space and time separately but in a four-dimensional spacetime. -It also states that gravity can be thought of as a curvature of spacetime. The Electromagnetic Interaction – Coulomb's Law (electrical interaction) -F=kQq/d2 -Unlike Gravity there are attractive and repulsive forces. -Like charges repel, opposite charges attract.

-The negative charge is the charge that is allowed to move. – Magnetic interaction -Magnetic fields are created by currents -Permanent magnets are caused by the net current of certain unpaired electrons in certain atoms, and are called Ferromagnets. -Contact Forces are inherently electromagnetic Interactions. Finding Forces – Gravity is present in a significant amount unless you are far from the earth or sun. Forces in Fluids – Pressure -P=F/A – A=Surface Area/Cross sectional area (Conditional) Pressure in Fluids – Pressure depends on depth. – Pressure is equal for any point at the same depth. – Pressure is independent of direction. – Pressure is normal to surface. Buoyant Force -The buoyant force is equal to the volume of the displaced fluid. Floating and Sinking – Density is mass per volume – In general, things that are less dense than the fluid surrounding them will float. Galilean Relativity – Consistent with Newtons Laws – Simply states that relative velocities can be simply summed to find net velocity – Breaks down close to the speed of light by experiment. Special Relativity – States that there is a universal speed limit, the speed of light 2.998x108 m/s. – Still assumes motion symmetry – This speed limit requires that time dilates, and that length contracts. The Twin Paradox – Special relativity is symmetric as long as no one accelerates.– If I travel somewhere and turn around I must accelerate! – Something different happens to accelerated observer.

Energy Associated symmetry is time translation Angular Momentum Associated symmetry is rotational. Charge -Associated symmetry too nasty Mass -Not fundamental conservation law -Related to conservation of energy – Fundamental particles -Not fundamental -Related to conservation of energy and charge. TEST 2 Energy -W=F*d - d is the distance over which the force acts Kinetic Energy -Energy related to Motion Potential Energy -Energy associated with forces acting on a body. Energy can change between forms but cannot be created or destroyed. Mechanical Energy – Macroscopic Internal Energy – Microscopic, typically related to heat or chemical energy. Kinetic energy – KE=1/2 mv2 – v is the velocity ● Gravitational Potential Energy –Ugrav=mgh – h is the height above the ground. Definitions of Waves –Mechanical Wave: A traveling ● Rutheford’s Scattering Experiment Used Alpha Particles – Positively charged particles of mass roughly equal to atoms (He nucleus) – Disproved plumb pudding model ● Solar System Model – Disprovedisturbance in material that transports energy – Equilibrium position: The point in the trajectory of a molecule in a wave where the net force is 0. Frequency (the pitch you hear) is the distance between peaks (not valleys) when intensity is plotted vs time -Wavelength is the length between intensity peaks when plotted vs space. Intensity is called amplitude (how loud it is) v=f

v=velocity f=frequency  =wavelength – How fast waves radiate out like ripples. Light -The speed of light is constant for any observer -The speed of light c=2.998x108 m/s -Light does not need a medium to travel -The equations that describe the propagation of light are known as Maxwell’s equations. There are four Maxwell equations, which include Coulombs law. ● Light diffracts, reflects, and refracts like a wave ● The equations that describe the propagation of light are known as Maxwell’s equations ● There are four Maxwell equations, which include Coulombs law.

Photon – Quantum particle of light Planck’s Constant – Constant related to the energy of a photon, such that E=hf. Temperature is a measure of the average kinetic energy of molecules in a substance. -As temperature increases, the average kinetic energy of molecules increase, and phases can change. – The change from a solid to liquid or liquid to a solid happens at the same temp. – The change from a liquid to a gas or a gas to a liquid happens at the same temp. Density is the ratio of mass to volume – =m/V -Density of solids is roughly constant, as are liquids, but the density of gases vary. -Items in a fluid that are less dense float, items denser than the fluid sink. Orbitals – Electrons in an atom occupy discreet energy states called orbitals. – The quantum model states that these orbitals are essentially 3D standing waves of electron density. –

Because these standing waves have quantized energy, when an electron transits from a higher energy orbital to a lower energy orbital, it emits a specific frequency of light. By using spectroscopy, one can use these discreet emissions of light to identify properties of individual atoms on the periodic table of element.

Chemistry An element contains only one kind of atom ● Atoms of different elements have different mass and different chemical properties ● Chemical compounds are composed of two or more atoms in fixed ratios ● Chemical reactions are the rearrangement of atoms to form different compounds ● Elements can be catagorized by their physical and chemical properties. Entropy is the quantitative measure of disorder in a system. As entropy increases the quality of energy decreases. Entropy is always increasing at large, the quality of energy is always decreasing. Mixtures – Solution ● A mixture containing two or more compounds at least one of which is a liquid – Alloys ● A solid solution of metals. Structure of matter – Atomic Matter ● Matter that contains singular atoms like noble gases in a solid liquid or gas. – Molecular matter ● Exists as a compound in common states. – Extended Bonding Substances ● An extended network of atoms or ions. Covalent – Atoms share bonding electrons. Covalent molecules quite often have a very polar nature, like water. Ionic – One atom steals the bonding electron from the other atom in the molecule. When in

solutions, ionic compounds tend to conduct electricity. They are then electrolytes. Covalent materials have very low electron mobility, and do not have high electrical or thermal conductivity. Seismic waves have two categories – P waves: Primary seismic wave, travels fastest, it is a compression wave – S waves: Secondary seismic wave, travels slower, and is a shear wave. Shadow zones are areas where seismic waves don’t travel to because of the refraction of the wave as it changes the medium it is traveling through. Because shear waves can only travel in a solid, we can determine that the earth has a liquid mantel, a liquid outer core, and a solid inner core by the shadow zones. Permanent magnets don’t work beyond the Curie Temperature, however the earth’s core is much hotter than the Curie temperature of iron. ● The earths magnetic field is driven by convection currents in the earths mantel. Gravity is constant no matter the distance from the earth (until you are in space) If a ball was rolling across the floor and stopped it is because of UNBALANCED FORCE not a loss of force. Hypothesis is an idea that something will work. A theory is an idea that was tested. Mass is the same as INERTIA Small object= easy change in motion Large object= hard to change the motion. The moon is in orbit by gravity. Earth to moon=same force different acceleration Meters per sec ^2 is the acceleration Meters per sec is speed or velocity. IF you have a skydiver falling and it reaches terminal velocity what are each balanced force pairs. Gravity and air

Acceleration towards earth= mass times 9.8 m/s Man with balloons-helium is less dense that air. It is displacing less air than it weighs. Law of inertia= Newtons 1st law Charges are due to electrons Closed current creates a dipole magnet. The first standing wave that looks like a closed current is D orbitals (the halo) An object submerged at the bottom of a pool: buoyant force is the volume displaced water. F=GMm (over r^2) Mac truck and Mosquitos Forces are equal but the acceleration is different because of mass. The mosquito accelerates a lot to make up for the difference in mass. Pressure=Force (over) Area Man and rock in boat: The water was already displaced so the water level wont change but the boat will rise higher in the water. Twin Paradox The wacky watch is in the ship because his velocity had to change. The twin in the sip would return looking younger. Inertial reference frame=undergoing no acceleration Non-inertial reference frame-undergoing acceleration The kind of wave if the particles are going in the same direction is a longitudinal wave.Transverse is ripples in a pond. The particle motion is perpendicular to the wave. Corrective lenses-refraction Hertz=1 (over) Seconds Transverse mechanical wave=shear wave (cant exist in fluids) Ripples are transverse waves but not transverse mechanical waves because transverse mechanical waves cant exist in a fluid. Frequency increases wavelength decreases. Red is the lowest frequency of light we can see Antinode-most particle motion

Red photons of red have lower energy Blue=higher energy Blue is the highest frequency of light we can see. Electron wave functions are standing waves with a change in frequency. Photons are the particles of light. Plum-pudding not true because charge is spread throughout atom. (-) charge has to be on the outside of the atom. Nucleus was the 1st part of the atom that was discovered heaviest part of the atom. Electrons take up the most space in an atom. Electrons have to jump from allowed orbital to allowed orbital with only the amount of energy they have.If an electron falls closer to the nucleus it will releases light. Light wiggles electrons. Down in energy=emitted light. U in energy-absorbs light. The solid state of ice is less dense than the liquid state (allows for life on earth) Bodies of water freeze from the bottom up....