Physics Cheat Sheet Exam Final 2 PDF

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Physics for Health Science - All equations, definitions and key information needed for the exam...

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s=d/t; a=F/m; a=v/t; I=V/R; I=q/t; P=e/t; W=VA

N1L: 'Law of Inertia' - An object at rest stays at rest & an object in motion stays in motion with the same speed & in the same direction unless acted upon by an unbalanced force ; N2L: The

a α  F /m

; acceleration of an object is directly proportional to the net force acting on the object, is in the direction of the net force, & is inversely proportional to the mass of the object. N N3L: For every action, there is an equal & opposite reaction; NL Cooling: states that the hotter an object is, the faster it cools; Accuracy the nearness of a measurement to the standard or true value; Precision consistency of repeated measurement; Margin of error is understood to be one half of the size of the last significant place; Scientific Notation 3,250,000,000 (9 units to LEFT) = 3.25 x 10 9; 0.0000004 (7 units to RIGHT) = 4 x 10 -7; Proportionality Direct - Same, Inverse - Opposite, Causative - independent, Affected - dependent; Distance is how much ground is covered by an object, regardless of its starting or ending position; Displacement does not take into account what route the object took to change position, only where it started and where it ended(??m L or R); Speed doesn’t indicate direction, just distance travelled vs. time elapsed d α t; Instantaneous speed is speed during a very brief period of time; Velocity is speed in a specific direction Δv = vfinal – vinitial ; Acceleration is when an object undergoes a change in its state of motion (whether speed, direction or both); acceleration is the time rate of change in velocity (m/s2) a = Δv/Δt can also be expressed as a = (vf – vi) / Δt; Freefall motion under the influence of gravity only; Velocity acquired in free fall from rest v=gt; Inertia is an apparent resistance of an object to change its state of motion and is a combination of velocity & mass; Force push or pull on an object 5

 N

+5

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= 10

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 N

+5

´ N

=5

 N

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= 0N; Net force sum of all forces;

Mechanical Equilibrium means net force is zero; Equilibrium can occur when an object is stationary (‘static’ equilibrium) or when an object is in steady straight line motion (‘dynamic’ equilibrium); Non Zero net force moving in a direction; Friction is opposing what we are applying; Mass (kg)is the quantity of matter in an object (a α 1/m); Weight (N) is the force on an object due to gravity w α m; Momentum is 'inertia in motion' or the tendency of a moving object to resist change to its motion: M = mv so ΔM = Δmv & ΔM α F & ΔM α t; Impulse (Ft = F x t) is the change in Momentum ΔM α Ft (Tennis Player & Catching a Ball); Work (J) is the product of the force on an object & the distance through which the object is moved by that force: W = Fd & 1J = 1N x 1m; Power is the quantity of work done per unit time P = W/t; The derived unit for power is the Wat (W) 1W = 1J/1s; Energy is the ability to do work, Energy is measured in Joules; Mechanical energy is the energy due to an object’s movement & relative position: It takes 2 forms – Potential: due to relative position & Kinetic: due to motion; Potential Energy - When an object has work done on it to put it in a certain position relative to another location (elastic band); Kinetic Energy - If an object is moving, it is capable of doing work, so it must have energy, the object received the energy from the thing that caused it to be put in motion KE = ½ mv2 ; Atom smallest piece of an element that keeps its chemical properties; Nucleus densely packed central area of atom contains protons (+ particle) and neutrons (neutral particle); Electron particle orbiting the nucleus of an atom with a negative charge; Element substance that cannot be broken down by chemical reactions (1 atom); Atomic number # of protons in nucleus; Atomic mass number # of protons & neutrons in nucleus; Ion atom loses (+ charged cation) or gains (- charged anion) electrons; Isotope one of two or more atoms with the same atomic number that contain different numbers of neutrons; Compound A substance that contains two or more elements CHEMICALLY combined in a fixed proportion (cake batter); Mixture A physical blend of two or more substances that are NOT chemically combined (trail mix); Molecules form when two or more atoms form chemical bonds with each other (H 2O, N2, C6H12O6); Bohr Model electrons travel in fixed orbits at set distances from the nucleus. The amount of energy each electron has is determined by which orbit it travels in. Electrons jump from one orbit to another only by emitting or absorbing energy in fixed quanta; Volume is the measure of the 3D space occupied by an object & is dependent on several factors: mass, Pressure (for gases), Temperature, State or phase, Deformation by forces; Density is the mass per unit volume of a material ρ=m/V; Elasticity is the relative quantity of temporary change to an object’s shape that occurs in response to the application of a deforming force to it; Deforming forces can be compressing (-) or stretching (+) in effect; Tension when something is pulled on (stretched) & Compression when something is pushed in (squashed) e.g. Bent ruler - outer curve tension, inner curve compression; Mater is anything that occupies space (has volume) & has mass. Matter is made up of atoms, takes four main states or ‘phases’: Solid Maintains a fixed volume & shape regardless of its container; changes shape only when broken or cut; atoms, molecules and ions are close together and in fixed spatial relationships to one another; vibrate in place; Liquid is nearly incompressible, maintains a relatively fixed volume regardless of pressure but has a variable shape that adapts to its container, atoms, molecules and ions are close together but move freely relative to one another; Gas takes the volume & shape of its container, atoms, molecules and ions are relatively far apart and move freely relative to one another with virtually no inter-molecular interactions; Plasma It can undergo a ‘physical change’ to change its state from one to another; Pressure is the ratio of quantity of force exerted to the area over which it is distributed P = F/A, 1 Pa = 1N/m 2 (bed of nails); A solid object exerts pressure due to its weight via its base surface only, not its sides. A liquid exerts the pressure due to its weight against the sides & bottom of its container; A fluid is something that flows, it includes liquids & gases. A liquid is something that takes the shape of the container, but holds its volume, where a gas takes the shape & volume of the container; Pressure α depth; Pressure α density; Flowing fluid requires a 'path' & 'push'; The result of pressure on fluid along a path: Volume Flow Rate (current) F = Av; The continuity of flow equation is A1v1 = A2v2; Pascals Principle - A change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid (full bladder, pregnant woman pressing on foetus, hydraulics); Bernoulli's Principle where the speed of a fluid increases, internal pressure in the fluid decreases (garden hose - squeeze end & water flows faster); Bernoulli’s Equation - P + ½ ρv2 + ρgh = constant (height↑Pressure↓, h↓P↑, volume flow rate↑Pressure↓, v↓P↑, height↑volume flow rate↓, h↓v↑); Laminar flow is in regular layers, Turbulence is chaotic flow (heart would have to pump harder to achieve the required flow rate); Laminar flow smooth steady flow (Little energy is removed from the system due to minimal friction); Turbulent flow chaotic (Increased energy is removed from the system due to friction, generating heat; Turbulence causes reduced flow rate relative to applied pressure (In the cardiovascular system, the heart would have to pump harder to achieve the required flow rate)); Crystalline solid molecules (or atoms) arranged in a lattice; Non-crystalline solid (amorphous) has no such regular arrangement of molecules; Poiseuille’s Law states that F is directly proportional to ΔP (drop) along the path & inversely proportional to R of the path to flow F = ΔP/R; For fluid to flow, it must have mechanical energy; Flow velocity is the distance travelled per unit time of fluid particles (not Quantity); Atmospheric pressure is the force per unit area exerted against a surface by the weight of air above that surface in the Earth's atmosphere; Temperature a measure of the average translational kinetic energy per molecule in a substance (°F, °C, °K); Absolute zero = 0° K = -273° C; Heat energy that flows from a substance of higher temperature to a substance of lower temperature (Calories or Joules); Internal Energy is the sum of all of the forms of kinetic energy plus potential energy within an object; Temperature does NOT measure the total internal energy; Heat is energy moving across a temperature gradient (ΔT); Kilocalorie 1000 calories (the heat required to raise the temp of 1kg water by 1°C); Specific heat capacity (c) is the quantity of heat (Q) required to change the temperature (T) of a unit mass (m) of a substance by 1 degree ΔT = Q/(cm) so if c doubles, ΔT must drop to one half; Mass is independent of temperature and pressure but volume may change with both; Thermal Expansion when temp of a substance is increased, its molecules jiggle faster and move farther apart; The Ideal Gas Law combines the relationships between pressure, temperature (K) & volume P1V1 /T1 = P2V2 /T2; KE Movement takes 3 forms Rotational, Vibrational & Collisional; Heat transfer All three involve the movement of energy across a temperature gradient (high to low) - Conduction (collisions transfer energy molecule to molecule; gas poor conductors), Convection (move molecules across temp gradient; fluids only not solids) & Radiation (some ALWAYS occurs; EM waves; only at surface); Boyle's Law - if the volume is halved, the pressure is doubled; & if the volume is doubled, the pressure is halved P1V1 = P2V2; Gases flow when there is a ‘pressure gradient’ (ΔP); Gas P&t - Pressure α temperature, P 1/T1 = P 2/T2; Wave Equation C = f λ; Vibration periodic wiggle in time; Wave wiggle in space and time; All waves have: Period the time needed for one complete cycle of vibration to pass a given point, Frequency the number of complete cycles occurring per period of time (Reciprocal of period), Amplitude maximum displacement from midpoint (equilibrium), Wavelength distance between successive troughs, crests or identical parts of a wave, Velocity of wave equal to the product of its wavelength and frequency (number of vibrations per second); Periodic motion a motion that is regular and repeating (Pendulum); Hertz SI unit of frequency. 1 Hz = 1 vibration per second; Displacement the action of moving something from its place or position; Phase defines the position of the wave at a point in time of its cycle; In Phase - same point, Out of Phase - different points; Intensity the power transferred per unit area; Transverse (water drop) Longitudinal (slinky); Wave propagation is any of the ways in which waves travel. With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse waves; A Compression is a region in a longitudinal wave where the particles are closest together; A Rarefaction is a region in a longitudinal wave where the particles are furthest apart; Interference pattern formed by superposition of different sets of waves that produces reinforcements (constructive) in some places and cancellation (destructive) in others; Standing wave stationary wave pattern formed in a medium when 2 sets of identical waves pass through the medium in opposite directions. Appears not to be moving; Node any part of a standing wave that remains stationary, a region of minimal or zero energy; Antinode any part of a standing wave with maximum displacement and maximum energy; Doppler Shif change of frequency due to motion; Receiver moving toward sound is a higher frequency, receiver moving away from sound is a lower frequency; fr = fs + Δf (where Δf is positive if the motion is toward and negative if the motion is away); Beat frequency is a fluctuating volume caused when you add two sound waves of slightly different frequencies together (2 tuning forks); Sound longitudinal wave phenomenon that consists of successive compressions and rarefactions of the medium through which the wave travels; Reflection sound is an ‘echo’; Refraction is the bending of a wave front’s direction as it changes the medium in which it travels; Energy wave absorption when a sound wave strikes an acoustical material the sound wave causes the fibres or particle makeup of the absorbing material to vibrate. This vibration causes tiny amounts of heat due to the friction and thus sound absorption is accomplished by way of energy to heat conversion; Natural frequency frequency at which an elastic object naturally tends to vibrate if it is disturbed and the disturbing force is removed; Resonance - when the frequency of incoming pulsed energy matches the natural frequency of an object; Loudness is our perception of sound quantity; Intensity is an objective measure of quantity of sound; Intensity = energy / (area x time), Power = energy / time, Intensity = power / area; Intensity Level baseline 10-12W/m2 = 0 bel, if new intensity is 10 -11 W/m2, that IL is 1 bel, if new intensity is 10-8 W/m2, that IL is 4 bel; 1 decibel = 0.1 bel 10 dB = 1 bel, Each increase of 10 dB represents 10x (10 1) increase in intensity; Human hearing tends to include frequencies from 20 Hz to 20 kHz; Sound above 20 kHz is ‘ultrasound’; Net -charge, surplus electrons are at surface, Net + charge, ‘holes’ are at surface; Ion an atom that loses or gains electrons and so acquires a charge; Ionization process of adding or removing electrons to or from the atomic nucleus; Coulomb SI unit of electrical charge; Coulombs Law - like charges repel, opposite charges attract, the closer the 2 charges, the stronger the force; F=K x Q 1Q2/d2; Conductors give up electrons easily & Insulators are tightly bound; Semiconductor device made of material not only with properties that fall between a conductor and an insulator but with resistance that changes abruptly when other conditions change, such as temp, voltage, & electric or magnetic field; Superconductor material that is a perfect conductor with zero resistance to the flow of electric charge; Grounding allowing charges to move freely along a connection from a conductor to the ground; Polarisation refers to separating opposites; Charge polarization The partial or complete polar separation of positive and negative electric charge in a nuclear, atomic, molecular, or chemical system; Electric dipole molecule in which the distribution of charge is uneven, resulting in slightly

opposite charges on opposite sides of the molecule; Electric Field fills the space around every electric charge or group of charges. strength α force; 1 V = 1 J/C; Electrical potential energy energy a charge has due to its location in an electric field; Electrical potential energy (J) per unit charge (C) at a location in an electric field, measured in Volts (V) often called voltage; Voltage electrical "pressure"; Volt SI unit of electrical potential; Potential difference difference in electric potential (voltage) between two points. Free charge flows when there is a difference and will continue until both points reach a common potential; ElectroMotive Force an energy provider (battery, power point, charged capacitor); Batery chemical energy is converted into electricity and used as a source of power; Electric Current flow of electric charge that transports energy from one place to another (measured in amperes), is electricity in motion; Ampere SI unit of electric current; Conduction electrons electrons in a metal that move freely and carry electric charge; Ohmic resistance resistance of a material to the flow of electric charge through it; Ohm's Law (I=V/R) current in a circuit is directly proportional to the voltage impressed across the circuit and is inversely proportional to the resistance of the circuit; Resistor device in an electric circuit designed to resist the flow of charge; Ohm SI unit of electrical resistance; Electric circuit any complete path along which electric charge can flow; Kirchoff’s Laws Current - entering=current leaving, Voltage - rise=drop; electrical energy = V x I x t, SI unit is W; Resistance α path length; Resistance α 1/area; Series Circuit (in-line) all or nothing; Parallel circuit (side by side) independent; Current waveforms AC↔ ᴖᴗ DC→ ᴖᴖ; ; Supply to home, switchbox with parallel circuits sends ; 240V 50hZ; Path of least resistance; Ground Fault Circuit Interrupt ( GFCI); Circuit Limiting Devices ( CLD) fuse (low melting point), circuit breaker (open the loop when max exceeded); Residual Current Device ( RCD) monitors device (open the loop); Electric shock - passing I thru,, becomes conducting path; Damage AC↑DC↓; Dry/Wet/Punctured skin; Surface area v; Macroshock - skin, Microshock - muscle; Switch device for making and breaking the connection in an electric circuit; Circuit overload happen when more amperage is put across an electrical wire or circuit than it can handle; Circuit breaker an automatic device for stopping the flow of current in an electric circuit as a safety measure; Fuse a type of low resistance resistor that acts as a sacrificial device to provide over current protection, of either the load or source circuit; Leakage current the unintended loss of electrical current or electrons; Short circuit low-resistance connection established by accident or intention between two points in an electric circuit. The current tends to flow through the area of low resistance, bypassing the rest of the circuit; Equipotential grounding an engineering manoeuvre in which all conductive surfaces of a hospital room are bonded to each other and to the Earth. This process is essential to preventing stray voltage that could affect vital medical equipment and potentially harm the patient; Electrocution is death caused by electric shock; Current density amount of electric current flowing per unit crosssectional area of a material; Magnetic force attraction of unlike magnetic poles for each other and the repulsion between like magnetic poles; Magnetic pole one of the regions on a magnet that produce magnetic forces; Magnetic field region of magnetic influence around a magnetic pole or a moving charged particle; Opp attract, likes repel; Force line (flux) N-S (inside S-N); Magnetic field strength The magnetic field can be visualized as magnetic field lines. The field strength corresponds to the density of the field lines; Magnetic domain a region within a magnetic material which has uniform magnetization. Individual magnetic moments of atoms are aligned with one another and they point in the same direction; Ferromagnetism is the basic mechanism by which certain materials (Fe, Co & Ni) form permanent magnets, or are attracted to magnets; Retentivity ability of a substance to retain or resist magnetization, frequently measured as the strength of the magnetic field that remains in a sample after removal of an inducing field; Permanent magnet an object made from a material that is magnetized and creates its own persistent magnetic field (fridge magnet); Electromagnet magnetic properties are produced by electric current; Solenoid coil wound into a tightly packed helix ; Electric motor an electrical machine that converts electrical energy into mechanical energy; The reverse conversion of mechanical energy into electrical energy is done by an electric Generator; Electromagnetic induction phenomenon of inducing a voltage in a conductor by changing the magnetic field near the conductor. If magnetic field within a closed loop changes, a voltage is induced in the loop; Flux The rate of flow of fluid, particles, or energy through a given surface, the lines of force of an electric or magnetic field; Flux linkage product of the magnetic flux and the number of turns in a given coil; Motor effect moving charge or current-carrying wire will experience a thrust (or deflection) when its magnetic field interacts with an external field...