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University of Miami
Physical Science
PSC 101

Physical Science Study Guide: Chapter 1  Meaning of static and dynamic equilibrium o When the forces on a stationary object add up to zero, the object is in equilibrium – static equilibrium o Dynamic equilibrium – when an object is moving at a constant speed in a straight-line path  Moves at an unchanging speed and direction o Net Force is zero for both equilibriums o An object under only one force cannot be in equilibrium  Mass and Inertia o Every material object possesses inertia; the more matter the more inertia o Mass is a measure of inertia of a material object  The quantity of matter in an object. It is also the measure of the inertia or the sluggishness that an object exhibits in response to any effort made to start it, stop it, or change its state of motion in any way. o Inertia – the property by which objects resist to changes in motion Vocabulary:  Acceleration- rate at which velocity changes w/ time in m/s^2  Air resistance- force of friction action on object due to motion in air  Equilibrium rate- all forces add up to 0  Force- a push or a pull  Free fall- falling only under influence of gravity; no air resistance  Friction- resistive force that opposes the motion/ attempted motion of an object past another with which its in contact  Inertia- the property of things to resist changes in motion  Mass- quantity of matter in an object  Net force- combination of all forces acting on an object  Speed- distance traveled per time  Support/normal force- force that supports an object against gravity  Vector- arrow representing magnitude and direction of a quantity  Velocity- the speed of an object and specification of its direction of motion  Volume- quantity of space an object occupies  Weight- force due to gravity on an object; force with which a body presses against a supporting surface  Mks units- expresses any given measurement using fundamental units of the meter, kilogram, and/or second (MKS) Chapter 2  Newton’s Three Laws o Newton’s First Law – the law of inertia:  An object at rest tends to remain at rest; an object in motion will remain in motion at a constant speed along a straight path  Property to resist change in motion is called inertia.  Objects undergo change in motion only in the presence of a net force o Newton’s Second Law – the law of acceleration  When a net force acts on an object, the object accelerates  Acceleration is directly proportional to the net force and inversely proportional to the mass  Acceleration is always in the direction of the force  When an object falls in a vacuum, the net force is simply the weight and the acceleration is g  When an object falls in air, the net force is equal to the weight minus the force of air resistance, and the acceleration is less than g o Newton’s Third Law – the law of action-reaction  Whenever one object exerts a force on a second object, the second object exerts an equal and opposite force on the first  Forces occur in pairs; one is an action the other is reaction; they always act on different objects; neither could exist without the other Vocabulary:  Force pair- the action and reaction pair of forces that occur in an interaction  Interaction- mutual action between objects during which each object exerts an equal and opposite force on the other  Newton’s first law- an object in motion stays in motion and an object at rest stays at rest unless acted on by a net force  Newton’s second law- the acceleration produced by a net force on an object is directly proportional to the net force, in the same direction  Newton’s third law- whenever one object exerts a force on another, the second object exerts an equal and opposite force on the first  Terminal speed- the speed at which the acceleration of a falling object terminates when air resistance balances its weight  Terminal velocity- terminal speed in a given direction (often downward) Chapter 3  Momentum – inertia in motion; mass of an object multiplied by its velocity o The greater the net force on an object, the greater its change in velocity and therefore the greater its change in momentum o Both the force and time interval are important in changing momentum  Force x Time = Impulse  Impulse-Momentum relationship – the impulse is equal to the change in momentum the impulse causes o The greater the impulse exerted on something, the greater the change in momentum  Law of Conservation of Momentum – In the absence of an external force, the momentum of a system remains unchanged o Momentum before and after collision is the same  Work-Energy Theorem o Emphasizes the role of change o Applies to increasing speed as well as decreasing speed  Power: relates work to the amount of time it takes to do that work o Rate at which energy is changed from one form to another Vocabulary:  Conservation of energy for machines- the work output of any machine cannot exceed the work input in an ideal machine, where no energy is transformed into thermal energy: Work (input) = work (output) and fd (input) = fd (output)  Efficiency- percentage of work put into a machine that is converted into useful work output Efficiency = useful work output/total work output  Elastic collision- a collision in which colliding objects rebound without lasting deformation of the generation of heat  Energy- the property of a system that enables it to do work  Impulse- product of the force acting on an object and the time during which it acts  Impulse momentum relationship- impulse is equal to the change in the momentum of an object that the impulse acts upon  Ft = Δ (MV)  Inelastic collision- a collision in which the colliding objects become distorted, generate heat, or possibly stick together  Kinetic energy- energy of motion, quantified by the relationship: KE= 1/2MV^2  Law of conservation of energy- energy cannot be created or destroyed; it may be transformed but the total amount of energy never changes  Law of conservation of momentum- in the absence of external force the momentum of a system remains unchanged MV (before) = MV (after)  Lever- a simple machine consisting of a rigid rod pivoted at a fixed point called the fulcrum  Machine- a device, such as a lever or pulley, that increases or decreases a force or simply changes the direction of a force  Momentum- inertia in motion, given by the product of the mass of the object and its velocity  Potential energy- energy mass possesses due to its position PE=mgh  Power- the rate of doing work  Work- product of the force and the distance moved by the force : W= FD  Work-energy theorem- net work done on an object equals the change in kinetic energy of the object Chapter 4  Law of Universal Gravitation o Everything pulls on everything in a simple way that involves only mass and distance o Any body attracts any other body with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance  Weight – the force that an object exerts on a supporting surface, which is not always, but often the force of gravity  Mass – doesn’t change with force, the amount of matter in your body  Projectiles and Satellites o Projectile – any object projected by its own means and continues in motion by its own inertia; the curved path is a combination of vertical and horizontal motion o Satellite – simply a projectile that falls around the Earth rather than into it; speed of the satellite must be great enough to ensure that its falling distance matched Earth’s curvature Vocabulary:  Ellipse- oval path followed by a satellite. The sum of the distances from any point on the path to 2 points called foci is a constant. When foci get farther apart, an eclipse becomes more eccentric  Escape speed- the speed that a projectile must reach to escape the gravitational influence of earth or any other celestial body  Inverse-square law- intensity of an effect from a localized source spreads uniformity throughout the surrounding space and weakens with the inverse square of the distance Intensity = i/distance ^L Gravity follows this law, as do effects of electric, light, sounds radiation phenomena  Law of universal gravitation- every body in the universe attracts another body with a force that is directly proportional to the product of the se masses and inversely proportional to the square of the distance separating their centers F= G (m x m2/d)  Parabola- curved path followed by a projectile under the influence of constant gravity only  Projectile – any object that is projected by some means and continues its motion by its own inertia  Satellite- a projectile or small celestial body that orbits a larger celestial body  Weightless- being without a support force, as in free fall Chapter Five Why do wings lift and baseballs curve?  Archimedes principle- an immersed body is buoyed up by a force equal to the weight of the fluid it displaces (for liquid and gas)  Atmospheric pressure- the pressure exerted against bodies immersed in the atmosphere resulting from the weight of air pressing down from above. At sea level, it is 101 kpa  Barometer- any device that measures atmospheric pressure  Bernoulli’s principle- the pressure in a fluid moving steadily without friction or external energy input decreases wen the fluid velocity increases  Boyle’s law- the product of pressure and volume is a constant for a given mass of confined gas regardless of change in either pressure or volume individually. As long as pressure remains unchanged: P1V2=P2V2  Buoyant force- the net upward force that a fluid exerts on an immersed object  Density- the amount of matter per unit volume: Density = mass/volume  Pascal’s principle- a change in pressure at any point in an enclosed fluid at rest is transmitted undiminished to all points in the fluid  Pressure- ration of force to the area over which the force is distributed Pressure = force / area Liquid pressure= weight density x depth  Principle of flotation- a floating object displaces a weight of fluid equal to its own weight Chapter 6  Temperature: the quantity that indicates how warm or cold an object is relative to some standard o When we measure the temperature of something with a conventional thermometer, thermal energy flows between the thermometer and the object whose temperature we are measuring o When the object and the thermometer have the same average kinetic energy per particle, we say they are in thermal equilibrium  Absolute Zero: the lower limit of temperature, molecules have lost all available kinetic energy  Heat: the thermal energy transferred from one thing to another due to a temperature difference o A substance does not contain heat, it contains thermal energy o Heat is thermal energy in transit  Specific heat capacity o Different substances have different thermal capacities for storing energy o Equal masses of different materials require different quantities of heat to change their temperatures o Water has a much higher capacity for storing thermal energy than almost any other substance  Various ways that energy can be absorbed  Thermal Expansion o As the temperature of a substance increases, its molecules jiggle faster and faster o Must be taken into account in structures and devices of all kinds o Expansion of water  Expands when heated, but doesn’t expand the temperature range between 0 celsius and 4 celsius  Ice has a crystalline structure, with open-structured crystals. Ice is less dense than water, so molecules in ice have more open space to move around. When ice melts, not all the open-structured crystals collapse. Some remain in the ice-water mixture, making up slush that bloats the water. As the temperature of water is increased from 0 celsius, more of the ice crystals collapse. The melting of these ice crystals further decreases the volume of water. Two opposite processes happen for water at the same time – contraction and expansion. Volume decreases as ice crystals collapse, while volume increases due to greater molecular motion. The collapsing effect dominates until the temperature reaches 4 degrees. After that expansion overrides contraction because most of the ice crystals have melted  Absolute zero- temperature at which no further energy can be taken from a system  Entropy- the measure of energy dispersal of a system; whenever energy freely transforms, the direction of transformation is always toward a state of greater disorder/ entropy  First law of thermodynamics- law of energy conservation applying to system involving temperature change  Heat- thermal energy that flows from a substance of higher temperature to a substance of lower temperature; measured in calories/ joules  Internal energy- total energy contained by a thermodynamic system.[1] It is the energy needed to create the system but excludes the energy to displace the system's surroundings. Includes kinetic and potential  Second law of thermodynamics- heat never spontaneously flows from a cold substance to a hot substance  Specific heat capacity- the quantity of heat required to raise the temperature of a unit mass of a substance by 1deg C  Temperature- measure of the hotness of substances, related to the average translational kinetic energy per molecule  Thermal energy- total energy (KE+PE) of the submicroscopic particles that make up a substance  Thermodynamics- the study of thermal energy and its relationship to heat and work  Third law of thermodynamics- no system can reach absolute zero Chapter 7  Conduction o Materials thermal energy travels quickly through are called conductors. Materials thermal energy travels slowly through are called insulators  Convection- o collective movement of groups or aggregates of molecules within fluids (e.g., liquids, gases) and rheids. Convection of mass cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids.  Phases o Matter exists in four common phases/states:  Solid (ex. Ice) – when thermal energy is added, the increased molecular motion breaks down the frozen structure and it becomes a liquid phase, water. When more energy is added, the liquid changes to the gaseous phase. Add still more energy and the molecules break into ions and electrons, giving the plasma phase.  Heat of Sublimation: the amount of energy that must be added to a mole of solid at a constant pressure to turn directly into a gas, 46.7 kJ Vocabulary:  Boiling- rapid state of evaporation that takes place within the liquid as well as on its surface  Condensation- change of phase from gas to liquid; opposite of evaporation. Warming of both results  Conduction- transfer of thermal energy in a gas or liquid by means of currents in the heated field  Evaporation- the change of phase at the surface of a liquid as it passes to the gaseous phase  Freezing- the process of changing phase from liquid to solid  Heat of fusion- amount of energy needed to change a unit mass of any substance from solid to liquid and visa versa  Heat of vaporization- the amount of energy needed to change a unit mass of any substance from liquid to gas and visa versa  Melting- the process of changing phase from solid to liquid  Newton’s law of cooling- the rate of loss of heat from a warm objects is proportional to the temperature difference between the object and its surrounding  Phase- the molecular state of a substance  Radiation- transfer of energy by means of electromagnetic waves  Sublimation – the change of phase directly from solid to gas  Terrestrial radiation- the radiant energy emitted by earth Chapter 8  Conservation of charge o Electrons and protons have electric charge; the total positive charge balances the total negative charge exactly o No case of the creation or destruction of net electric charge has ever been found. o An object that is electrically charged has an excess or deficiency of some whole number of electrons – electrons cannot be divided into fractions of electrons  Coulomb’s Law o States that for two charged objects that are much smaller than the distance between them, the force between them varies directly as the product of their charges and inversely as the square of the separation distance o Electrical force decreases inversely as the square of the distance between charges  Electric Field o An energetic aura that extends through space; it’s a vector quantity, having both direction and magnitude  Electric Potential Energy o The energy possessed by the charged particle that is due to its location o Electric potential – the concept of potential energy per charge  Electric Power: the rate of energy transfer, or the rate of doing work; the amount of energy per unit time o Power is measured in watts  Alternating current- an electric current that repeatedly reverses its direction; the electric charges vibrate about relatively fixed points  Ampere- the unit of electric current; the rate of flow of 1 coulomb of charge per second  Conductor- any material having free charged particles that easily flow through it when an electrical force acts on them  Coulomb- the SI unit of electric charge. One coulomb ( C ) is equal in magnitude to the total charage of 6.25 x 10^18 electrons  Coulomb’s law- the relationship among electrical force, charge, and distance. If the forces are alike in sign, the force is repelling, if the charges are unalike, the force is attractive  Direct current- an electric current flowing in one direction only  Electric current- the flow of electric charge that transports energy from one place to another  Electric field- defined as force per unit charge, it can be considered an energetic aura surrounding charged objects. About a charged point , the field decreases with distance according to the inverse- square law, like a gravitational field. Between oppositely charged parallel plates, the electric field is uniform  Electric potential – the electric potential energy per amount of charge, measured in volts and often called voltage  Electric potential energy- the energy a charge possesses by virtue of its location in an electric field  Electric power- the rate of energy transfer or the rate of doing work, the amount of energy per unit time which can be measured by the produce of currents and voltage: power= current x voltage It is measured in watts or kilowtts where 1 A x 1 V = 1W  Electrical resistance- the property of a material that resists the flow of an electric current though it, measured in ohms (Ω)  Electrically polarized- term applied to an atom or molecule in which the charges are aligned so that one side has a slight excess of positive charge and the other side a slight excess of negative charge  Ohm’s law- the current in a circuit varies in direct proportion to the potential difference or voltage and inversely with the resistance: current = voltage/ resistance A current of 1A is produced by a potential difference of 1V across a resistance of 1 Ω  Parallel circuit- an electrical circuit with two or more devices connected in such a way that the same voltage acts across each one, and any single one completes the circuit independently of all the others  Potential difference- the difference in potential between tow points, measured in volts and often called voltage difference  Series circuit- an electrical circuit with devices connected in such a way that the current is the same in each device  Superconductor- any material with zero electrical resistance in which electrons flow without losing energy and without generating heat Chapter 9  Domains and iron magnets o Permanent magnets can be made by placing pieces of iron or similar magnetic materials in a strong magnetic fields o Alloys of iron differ: soft iron is easier to magnetize than steel  Magnetic force on a moving electric charge o The charged particle experiences a deflecting force F=qvB o The force is greatest when the particle moves in a direction perpendicular to the magnetic field lines o Other angles it is less o It is zero when the particle moves parallel to the field lines o This is not the same as gravitational forces, electric forces, or magnetic forces between poles. Vocabulary:  Electromagnet- a magnet whose field is produced by an electric current. It is usually in the form of a wire coil with a piece of iron inside the coil  Electromagnetic induction- the in
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