Physics Preliminary Course Overview

Physics Preliminary 8. 2 The World Communicates 1. The hustle model polish offer be employ to explain how electric automobile sure technologies conveyance randomness 1. obtain out the strength fractures required in bingle of the inte take a breath Mobile teleph wholeness Fax/modem Radio and television A. An power transformation is a transpose in the type of naught, for example a dislodge from sullen goose egg to electrocharismatic rocks.Relating this to the mobile reverbe range, it undergoes basic postal code transformations of, effective ruffle (your voice), to galvanizing energy (in the outfits within the ph whizz), to electroattractionic draw ins (from the ph unriv anyed to the tower), to galvanizing energy (at the tower), then to electromag sackic waves (to r to severally one the receiving ph atomic number 53), then voltaical energy (inside the receiving phone), then to plump waves (at the speaker of the receiving phone) 2. let on waves as a commute of energy disturbance that may occur in one, ii or three dimensions, depending on the genius of the wave and the strength A.Waves carry energy and well-nightimes they require a moderate and sometimes they dont. laser opens atomic number 18 an example of a 1 Dimensional wave, water waves are an example of a 2D wave man an example of 3D waves is a sound wave 3. happen upon that mechanical waves require a in enclosureediate for propagation while electromag illuminateic waves do non A. automatic waves, such as sound waves, water waves and soilquake waves exact a middling (a substance) to travel by, they understructurenot track down from one head teacher to another if in that respect is nothing (a vacuum) among the both points.On the other bowl over electromagnetic waves do not need a medium to travel through. An example of this is in post, which is a vacuum, if you call proscribed in space your sound waves do not penetrate out of your space suit. How ever electromagnetic waves do, and then you can see the cast down from the sun. Even simpler, in space you can see a woodworking planet explode, still you cannot hear it. 4. Define and chip in the following monetary assess to the wave model medium, displacement, bounteousness, period, compression, rarefaction, crest, trough, thwartwise waves, longitudinal waves, relative frequency, wavelength, and hurrying A.Mechanical Waves The comp some(prenominal) of waves that required a medium for transmission, e. g. sound waves Electromagnetic Waves The separate of waves that do not require a medium for transmission i. e. unseeable light, visible light etc. They all travel at the identical animate in a vacuum, which is the cannonball along of light. Transverse Waves Waves in which the jots thrill at right hang ins to the pleader of gesticulate of the wave, e. g. scrape up water waves. marrow of Propagation The direction of motion of a waveLongitudinal Waves Waves in w hich the particles oscillate replicate to the direction of motion of the wave e. g. sound. Periodic Waves Wave disturbance that take on themselves at regular intervals. Compressions Regions of a longitudinal wave where the particle are close together. The point where the medium has a maximum density Rarefactions Regions of a longitudinal wave where the particles are spread apart. The point where the medium has a minimum density. Crest The point of a wave where the particles of the medium work a maximum displacement upwards or in a positive direction.Trough The point of a wave where the particles of the medium nominate a maximum displacement downwards or in a damaging direction Amplitude The maximum displacement of the particles of a medium from their rest position Wavefront An imaginary seam joining any group of adjacent particles that are in a phase with each other. Wavelength The surmount between any both corresponding points of a wave oftenness the number of waves that take a point in one certify Period Number of crest passages per social unit time. 5. draw off the kind between particle motion and the direction of energy propagation in transverse and longitudinal waves A.Particles in the medium move in a direction perpendicular to the motion of transverse wave. Particles in the medium move in a direction of parallel to the motion of longitudinal waves 6. Quantify the relationship between amphetamine, frequency and wavelength for a wave A. V=fw (v= speed, f= frequency, w=wavelength) 2. Features of a wave model can be employ to reputation for the properties of sound 1. distinguish that sound waves are vibrations or oscillations of particles in a medium A. Sound is a longitudinal wave that requires a medium to travel through.As compressions and expansions (or rarefactions) of particles that pick out up the medium, sound is a vibration of the medium. 2. cogitate compressions and rarefactions of sound waves to the crests and troughs of trans verse waves utilize to represent them A. Compressions Regions of a longitudinal wave where the particle are close together. The point where the medium has a maximum density Rarefactions Regions of a longitudinal wave where the particles are spread apart. The point where the medium has a minimum density. Crest The point of a wave where the particles of the medium perk up a maximum displacement upwards or in a positive direction.Trough The point of a wave where the particles of the medium possess a maximum displacement downwards or in a negative direction 3. con make qualitatively that tar is related to to frequency and volume to amplitude of sound waves A. Frequency is the number of waves that pass a point in one second while the pitch is related to the number of vibrations per second. The pitch of a sound relates to the frequency of the sound emitted while the amplitude relates to the volume of that sound. E. g. if you permit a steep amplitude you lead have a loud sound.Whe n the frequency increases so does the pitch. 4. relieve an echo as a condemnation of a sound wave A. An echo occurs when a sound wave is reflected off a issue and returns to the source. 5. Describe the principle of superposition and match the resulting waves to the original waves in sound A. When two separate waves meet they can be added to or subtracted to make a new wave. An example of this with sound waves is, if you have one soul shout, and then you get two people to shout, each at the alike volume as the first person, the resulting volume will be the articulation of the two volumes. . Recent technological developments have allowed greater use of the electromagnetic spectrum 1. Describe electromagnetic waves in terms of their festinate in space and their lack of requirement of a medium for propagation A. Electromagnetic waves do not need a medium to travel through because electromagnetic waves do not vibrate particles so they dont need a vaccum. In space (a vacuum) elect romagnetic waves travel at the facilitate of light, a constant equal to 2. notice the electromagnetic wavebands filtered out by the atmosphere, especially UV, X- shaft of lights and gamma rays A.The Earths atmosphere provides a everyplaceprotective shield from harmful electromagnetic radiation. Fortunately this portion of the EM spectrum (UV rays, X-rays and da Gamma rays) is filtered by the Earths atmosphere. Earths atmosphere filters out most of the electromagnetic waves except for visible light and radio waves. 3. Identify methods for the detection of various wavebands in the electromagnetic spectrum A. Radio waves are detected with radio receivers that are attached to aerials. Microwaves are detected with piezo electric car crystals. visual light is detected by photoelectric cells. 4.Explain that the relationship between the ability of electromagnetic radiation and distance from a source is an example of the reverse firm constabulary A. The strength of a point is proportional to the square of the distance from the source of that symbol. This means that at twice the distance the signal has 1? 4 of its original strength. 5. Outline how the modulation of amplitude or frequency of visible light, microwaves and/or radio waves can be use to transmit information A. Modulation is the process of conveying a contentedness signal inside another signal that can be physically communicable.With amplitude modulation (AM), the amplitude or strength of the carrier signal is varied, which corresponds to substitutes in the sound, while its frequency keep ons constant. With frequency modulation (FM), the frequency of the carrier wave is altered according to mixtures in sound while the amplitude remains constant. 6. Discuss problems recrudesced by the limited revolve of the electromagnetic spectrum available for chat purposes A. There is only a limited range of wavelengths in the electromagnetic spectrum that can be used for discourse purposes. 4.Many communication technologies use applications of reflection and refraction of electromagnetic waves 1. Describe and apply the law of reflection and explain the effect of reflection from a plane originate on waves A. Reflection is the bouncing of a wave when it hits a surface or obstacle. Reflections of all types of waves follow the law of reflection. be given of Incidence = Angle of Reflection The law of reflection states that the tumble of the incident wave mustinessiness equal the run of the reflected wave and the incident wave and the reflected wave must lie in the aforesaid(prenominal) plane.It is important to remember that the angle of incidence and the angle of reflection is striped from the normal. The normal is perpendicular to the plane of reflection (e. g. a mirror). 2. Describe ship canal in which applications of reflection of light, radio waves and microwaves have assisted in information transfer A. Reflection of light is used fibre optics and in CDs. Fibre optics allow for massive add ups of information transfer. Reflection of radio waves are utilised when radio waves are reflected off the ionosphere. Television and radio use this reflection to transfer information. . Describe one application of reflection for each of the following Plane surfaces Concave surfaces planoconvex surfaces Radio waves being reflected by the ionosphere A. Reflection on a plane surface is used in applications such as, CD-ROM, where the laser beam is either reflected of the CD or not. Reflection of convex surfaces is used in surety mirrors, where it widens the topic of view. Reflection of concave surfaces is used in torches, where the rays of light change of location foulwards are projected forward, for more(prenominal) brightness. It is also used in satellite dishes.The ionosphere reflects a percentage of radio waves sent up, back towards earth. This allows for entropy to be sent through the radio waves over long distances. 4. Explain that refraction is related to the velocities of a wave in divergent media and system how this may result in the bending of a wavefront A. deflexion is the bending of light as it changes animate upon entering a medium with different optical density. 5. Define deflective index in terms of changes in the swiftness of a wave in passing from one medium to another A. The refractive index of a medium is the change in speeding of a wave from one medium to another.Therefore refractive index is related to the speed of a wave in that medium 6. Define Snells Law A. 7. Identify the conditions necessary for lend home(a) reflection with reference to the critical angle A. The critical angle is the angle of incidence, which forms an angle of refraction at 90. If the angle of incidence is little than the critical angle then you will have normal refraction, and if the angle of incidence is greater than the critical angle then you will have score internal reflection. 8. Outline how total internal reflection is used in optical fibres A.Optical fibres work by having one medium surface by another medium with a pooh-pooh refractive index. The angle that enters this is greater than the critical angle so in that respectfore the ray of light bounces nigh inside and travels from one end to another, never exiting the fibre. Therefore a light ray can travel through the wire. The ray of light never has an angle of incidence of little than the critical angle, so the ray never escapes the optical fibre. 5. Electromagnetic waves have emf for future communication technologies and data storage technologies 1.Identify types of communication data that are stored or transmitted in digital form A. Digital data is data that can be defined by numbers. Examples of digital communication include fax, Internet, telephone calls, etc 8. 3 Electrical aptitude in the Home 1. Society has get under ones skin increasingly internal energy dependent on electricity over the last 200 year 1. Discuss how the main sources of domestic energy have changed over time A. The first main source of domestic energy used by humans was fire, through wood, and then came domesticated animals, wind and water, coal, coal gas, electricity, fuel oils, solar and lastly nuclear energy.These have developed from the start of human existence to now. 2. Assess some of the impacts of changes in, and change magnitude access to, sources of energy for a community -More pollution -More demand for electrical energy -More electrical devices -Increased demand for energy 3. Discuss some of the ways in which electricity can be provided in remote locations utility(a) power sources can be used, such as solar or wind. 2. One of the main advantages of electricity is that is can be moved with comparative degree ease from one place to another through electric lots . Describe the behaviour of electrostatic vote outs and the properties of the surface areas associated with them A. An aim becomes electrostatically aerated when there is either a deficiency or excess of electrons. The two types of arraign are called positive mission and negative aid. Electrostatic load ups cause rushd particles to move of change direction. Electrostatic commissions create a playing field of charge. An electric field is a region in which a charged particle will experience a make. 2. Define the unit of electric charge as the coulomb. A.The SI unit of charge is the coulomb (C). A charge of 1 C is equal to the charge provided by 6. 25 x 10 (to the power of 18) electrons. This gives a charge of -1. 6 x 10 (-19 power) C for one electron. One coulomb is defined as the amount of charge that passes a point when a modern of one vitamin A ladders for one second. 3. Define the electric field as a field of force with a field strength equal to the force per unit charge at that point 4. Define electric current as the rate at which charge run aways (coulombs/ second or amperes) under the stoop of an electric field A.Electric current is defined as the amount of electric charge flowing past a given point in a given time interval. The SI unit of electric current is coulombs per second (C. s-1) or ampere (A), 1 amp is equal to 1 coulomb of charge passing a given point in 1 second. Conventional current runs from + to -. The electron movement is in the other direction of conventional current. 5. identify that current can be either direct with the net flow of charge carriers moving in one direction or alternating with the charge carriers moving backwards and in front periodically A. AC current involves the oscillation of electrons due to an electric field that is constantly changing direction. Most generators produce alternating current by means of a coil rotating in a magnetic field. With DC current flow, the electrons in a wire have an overall flow in only one direction. This is the method used in batteries, torches, takeout radios, lights in cars, and toys. 6. Describe electric potential divergence ( e mf) between two points as the change in potential energy per unit charge moving from one point to the other (joules/coulomb or volts). A. 7.Discuss how potential loss changes at different points about a DC set A. Voltage or potential difference is defined as the change in energy when one unit of charge is moved from one point to another or the work done to move one unit of charge from one point to another. Decreases as it move roughly the round. 8. Identify the difference between conductors and insulators A. -A conductor is a substance in which there are free charged particles and so a charge is able to flow through it. -An insulator is a substance in which free charged particles are limited and so a charge is not able to flow through it. . Define vindication as the ratio of potency to current for a particular conductor 10. Describe qualitatively how each of the following affects the movement of electricity through a conductor A. Length The longer the somatic the higher the resistance is. busy sectional area The larger the cross sectional area the lower the resistance is. So the thicker the wire then lower the resistance. Temperature The higher the temperature of a material, the higher the resistance is. Material Different materials have different resistances. This is called the resistor of that material. . Series and parallel circuits serve different purposes in households 1. Identify the difference between serial publication and parallel circuits A. A Parallel circuit is a closed circuit in which the current divides into two or more paths forward recombining to complete the circuit. A series is a circuit having its move connected serially Advantages of victimisation parallel circuitry over series circuitry in household wiring include You can have some devices on and others off at the same time. If one device fails the others still work. every last(predicate) devices receive the highest possible voltage. 2.Compare parallel and series ci rcuits in terms of voltage across factors and current through them A. In a parallel circuit the voltage is the same throughout the whole circuit while the current is divided between evenly throughout the circuit. In a series circuit the current is the same throughout the circuit while the voltage is divided evenly through the components of the circuit. 3. Identify uses of ammeters and voltmeters A. Ammeters are used to measure current. Voltmeters are used to measure voltage. To measure the voltage of a component the voltmeter is placed in parallel with the component.To measure the current passing through a component, the ammeter is placed in series with the component. When an ammeters work best if they have a low resistance. And voltmeters work best if they have a high resistance. 4. Explain why ammeters and voltmeters are connected differently in a circuit A. Voltage is sometimes called potential difference. So it is measuring the difference between two points, so is must be place d in parallel so that it can measure the difference between before and after that component. Current is a measure of the rate at which charge flows, and therefore must be connected in series.Ammeters have a low resistance. 5. Explain why there are different circuits for lighting, heat energy and other appliances in a house A. Because if they were all on the same circuit there would not be enough power to run all the appliances so they are spread out on several(prenominal) circuits so there is enough power. 4. The amount of power is related to the rate at which energy is transform 1. Explain that power is the rate at which energy is change from one form to another A. Power is the term used to describe how quickly energy (otherwise known as work) is transformed from one form to another, or transmitted from one point to another. . Identify the relationship between power, potential difference and current A. 3. Identify that the total amount of energy used depends on the length of time the current is flowing and can be calculated exploitation life force = VIt A. Energy = Voltage ? Current ? Time Energy = Power ? Time Energy is measured in joules (J). 4. Explain why the kilowatt-hour is used to measure electrical energy consumption rather than the joule A. 1 kWh is 1 kW every hour. The kWh is used to measure energy consumption. 5. Electric currents also produce magnetic fields and these fields are used in different devices in the home . Describe the behaviour of the magnetic impels of bar magnets when they are brought close together A. Magnetic fields are from north to south. When two bar magnets are brought close together the magnetic fields round their gats will produce a force between the two magnets. If two like poles (north pole and north pole OR south pole and south pole) are brought close together they will repel each other while if two unlike poles (a north pole and a south pole) are brought close together they will attract each other. Like poles r epel Unlike poles attract. 2.Define the direction of the magnetic field at a point as the direction of force on a very small north magnetic pole when placed at that point A. The direction of a magnetic field at any point is defined as the direction the north pole of a compass would indicate at that point. 3. Describe the magnetic field around p pedigrees of magnetic poles A. The magnetic field around pairs of magnetic poles is best depict by describing the lines of magnetic flux. Lines of flux are directed from the north pole to the south pole and never cross. In a strong magnetic field they are close together while in a weak magnetic field they are well apart. . Describe the product of a magnetic field by an electric current in a straight current carrying conductor and describe how the right hand grip rule can determine the direction of current and field lines A. When current is passed through a conductor, a magnetic field is created around it. The direction of the magnetic field can be found using the right hand rule. Point your right hand thumb in the direction of the current and the direction of your fingers is the direction of the magnetic field. 5. Compare the nature and generation of magnetic fields by solenoids and a bar magnet A. A solenoid is coil of wire.When a current is passed though a solenoid, a magnetic field similar to that of a bar magnet is produced. 6. preventative devices are important in household circuit 1. Discuss the dangers of an electric shock from both a 240volt AC mains supply and various DC voltages, from appliances, on the muscles of the luggage compartment A. There are several dangers when the muscles of the body are exposed to electric shocks. These are Pain receptors are usually activated. spontaneous contraction of the muscles usually means that the person will not be able to let go of the power source. The heart is stunned and goes into fibrillation. barren burns are inevitable. Instant death often occurs. 2. Descr ibe the functions of circuit breakers, commingles, earthing, double insulation and other safety devices in the home A. range Insulating works by wrapping or encasing the electric components of an appliance with insulating material The insulating property of these materials sets up a physical barrier to prevent the flow of electricity from the electric appliance to its user. A fuse is a con piece of an alloy of lead and tin, connected in series with the devices that it controls. The fuse is designed to melt when the current passing through it exceeds its threshold value. spell Breakers breaks the circuit when the current passing through it exceeds the threshold value by mechanical means The active and neutral wires are connected to the functional electric unit of the appliance to deliver electricity. The earth wire is attached to the case of the appliance, which is made of metal. 8. 4 Moving About 1. Vehicles do not typicly travel at a constant speed 1. Identify that a typica l journey involves speed change A. doubtfulness occurs when an objective changes its position relative to other objects or within some arrange system.A frame of reference is an object or a coordinate system that can be used to describe or compare motions. At the start of a journey your speed is 0 by the end of the journey you would have had to stop at traffic lights go up and down hills and e. g. 2. Distinguish between the fast and average speed of fomites and other bodies A. Average Speed Is your total distance taken by the time it took you to go that distance. Instantaneous Speed is the speed that you are travelling at any given instant 3. Distinguish between scalar and vector quantities in comparabilitys A. Scalar uantites have a magnitude tho no direction examples include distance, speed and time. Vector quantities have a magnitude and a direction. Examples include velocity, force and displacement 4. Compare instantaneous and average speed with instantaneous and average vel ocity A. Instantaneous speed is a scalar quantity, on the other hand instantaneous velocity is a vector quantity. Average speed is also a scalar quantity and average velocity is a vector quantity. Average speed takes into composition your whole journey, where as average velocity only takes into account the starting and ending points. 5. Define average velocity asA. 2. An epitome of the immaterial forces on fomites helps to understand the cause of speedup and deceleration 1. Describe the motion of one body relative to another A. doing occurs when an object changes its position relative to other objects or within some coordinate system. e. g. You are watching Coyote chase Road stolon. Road Runners velocity is 17 m. s east and Coyotes velocity is 15 m. s east. Road Runners velocity RELATIVE to you is 17 m. s east. Road Runners velocity RELATIVE to Coyote is 2 m. s east. 2. Identify the usefulness of using vector diagrams to assist solving problems A.Vector diagrams are used to a dd vectors, to find the resultant vector. This can be used to find the net force on an object from many smaller forces. Addition of vectors is also used to find total displacement 3. Explain the need for a net impertinent force to act in order to change the velocity of an object A. An object remains at rest, or in equivalent motion in a straight line unless acted on by an external force. This is also known as the law of inertia. It basically means that a moving object will travel in a straight line at a constant velocity until an external huffy force acts pon the object. 4. Describe the actions that must be taken for a vehicle to change direction, speed up and slow down A. As stated by normalitys 1st law of motion, in order to change a vehicles direction or speed, you need an external force, to act on the vehicle. However on earth there is, gravity, air resistance and friction to slow a car down, and trust from the locomotive engine and friction with the ground and the tyres to speed up a car. 5. Describe the typical effects of external forces on bodies including Friction between surfaces send out resistance A.Friction examples are constantly seen throughout a normal day and it normally slows you down or helps change direction 6. Define average quickening as A. 7. Define the terms mass and weight with reference to the effects of gravity A. Mass is the amount of matter in a body whereas weight is the force due to gravity playing on that mass. saddle is equal to mass times force due to gravity, which on earth is 9. 8 m. s. This is an extension of newtons 2nd law of motion. F=ma 8. Outline the forces involved in causing a change in the velocity of a vehicle when Coasting with no pressure on the accelerator Pressing on the accelerator Pressing on the brake Passing over an icy patch on the road uprise and descending hills Following a curve in the road A. 9. empathize Newtons Second Law of Motion and relate it to the equation A. The net force of a n object is equal to the product of its mass and its acceleration in the direction of the force. 10. Identify the net force in a wide variety of situations involving modes of transport and explain the consequences of the application of that net force in terms of Newtons Second Law of Motion A. Net force is defined as the vector sum of all forces.The net force is the resultant force of all individual forces performing on an object at that time. If the net force is zero, then the forces acting are described as balanced. The object will obey Newtons first law of motion, that is, it will either continue to move at a constant velocity or remain stationary. If the net force is not a zero value, it is described as an unbalanced force. In this case, the object follows Newtons second law of motion and acceleration will result. 3. Moving vehicles have kinetic energy and energy transformations are an important aspect in understanding motion . Identify that a moving object possesses kinetic ene rgy and that work done on that object can increase that energy 2. Describe the energy transformations that occur in collisions Elastic potential energy is the energy stored in ductile materials as the result of their stretching or compressing. In an elastic collision, the EK after the collision is equal to the kinetic energy before the collision. inflexible collisions result in the transformation of energy into other forms. It is usually muddled to the surroundings in the form of heat or sound and is no longer in a useful form. . Define the law of saving of energy Energy can neither be created nor destroyed but can be transferred from one body to another or transformed from one type to another. 4. Change of momentum relates to the forces acting on the vehicle or the driver 1. Define momentum as Momentum is a measure of an objects inclination to move in a straight line with constant speed. Momentum is the product of mass and velocity p ? mv 2. Define impulse as the product of fo rce and time whimsey is force applied over a period of time inclination = Force (Times) Time 3.Explain why momentum is conserved in collisions in terms of Newtons Third Law of motion In any collision, the total momentum before the collision is equal to the total momentum after the collision 5. Safety devices are utilised to recoil the effects of changing momentum 1. Define the inertia of a vehicle as its tendency to remain in uniform motion or at rest The inertia of a vehicle is its tendency to remain at rest or in uniform motion unless acted on by an external force. That is why when you crash a vehicle into a wall, it will continue to collide and squash into the wall instead of conscionable stopping.This is also why a passenger in a vehicle continues to go forward when the breaks of a vehicle are applied. Because the car may have forces slowing it down but the passenger has a tendency to continue forward 2. Discuss reasons why Newtons first off Law of Motion is not apparent in many tangible world situations There is always some type of friction that will oppose motion. Whether it is air resistance or friction between the object and the surface it travels on, it is impossible to completely eliminate friction. This is why objects do not remain in uniform motion. 3.Assess the reasons for the introduction of low speed zones in built-up areas and the addition of air bags and crumple zones to vehicles with respect to the concepts of impulse and momentum Air Bags and Crumple Zones both increase the stopping distance of a vehicle. Relating back to Impulse = Force ? Distance, If the distance is increased, the force is lower, this reduces the forces put on an the vehicle, and the occupants inside it. Low Speed zones are in place because, the slower your velocity, the less momentum you have and the faster you can stop 4. Evaluate the dominance of some safety features of motor vehicles 8. 5 The Cosmic Engine