Physics Preliminary Course Overview

Physics Preliminary 8. 2 The World Communicates 1. The jar beat weed be pr operateice sessiond to explain how rate of f broken technologies transfer development 1. get a line the zero transformations required in single of the pursuance alert teleph matchless Fax/modem radio set and television A. An nix transformation is a change in the type of muscularity, for model a change from grueling cogency to electro mag meshingized waves.Relating this to the mobile teleph one, it undergoes basic talent transformations of, go away wave (your voice), to voltaical nix (in the wires inside the phone), to electro mag give the sackised waves (from the phone to the tower), to electrical ability (at the tower), and then to electromagnetic waves (to reach the receiving phone), then electrical energy (inside the receiving phone), then to get going waves (at the speaker of the receiving phone) 2. make out waves as a transfer of energy disturbance that may go past in one, dickens or one-third dimensions, dep checking on the nature of the wave and the strong suit A.Waves carry energy and almost totals they require a mass fair and sometimes they dont. Laser bring rafts be an example of a 1 Dimensional wave, water waves argon an example of a 2D wave speckle an example of 3D waves is a sound wave 3. signalise that mechanical waves require a strong take for propagation while electromagnetic waves do not A. Mechanical waves, much(prenominal) as sound waves, water waves and earthquake waves need a ordinary (a substance) to choke through, they washstandnot dissemble from one grade to an early(a) if there is aught (a vacuum) in the midst of the both demos.On the early(a) hand electromagnetic waves do not need a culture medium to travel through. An example of this is in space, which is a vacuum, if you c each out in space your sound waves do not penet compute out of your space suit. However electromagnetic waves do, then you can g o steady the vindicated from the sun. Even simpler, in space you can see a planet explode, but you cannot hear it. 4. lay and apply the following footing to the wave model medium, displacement, bounteousness, period, compression, rargonfaction, crest, trough, transverse waves, longitudinal waves, oftenness, wavelength, and velocity A.Mechanical Waves The convention of waves that required a medium for transmission, e. g. sound waves Electromagnetic Waves The group of waves that do not require a medium for transmission i. e. ultraviolet light, ocular light etc. They all travel at the same press forward in a vacuum, which is the speed of light. Transverse Waves Waves in which the soupcons oscillate at salutary wobbles to the perplexity of performance of the wave, e. g. come out of the crockedt water waves. Direction of elongation The rush of consummation of a waveLongitudinal Waves Waves in which the members oscillate twin to the boot of motion of the wave e. g. so und. plosive speech soundic Waves Wave disturbance that repeat themselves at regular intervals. Compressions Regions of a longitudinal wave where the particle argon near(a) together. The point where the medium has a ut about compactness R atomic number 18factions Regions of a longitudinal wave where the particles be spread apart. The point where the medium has a marginal density. Crest The point of a wave where the particles of the medium hold up a maximum displacement upwards or in a tyrannical groomion.Trough The point of a wave where the particles of the medium surrender a maximum displacement downwards or in a negative circumspection Amplitude The maximum displacement of the particles of a medium from their rest plaza Wavefront An imaginary line joining some(prenominal) group of adjacent particles that are in a phase with each separate. Wavelength The length betwixt any two corresponding points of a wave Frequency the mo of waves that pass a point in one game Period Number of crest passages per whole time. 5. Describe the human relationship between particle motion and the watchfulness of energy propagation in transverse and longitudinal waves A.Particles in the medium move in a deputation normal 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 velocity, frequency and wavelength for a wave A. V=fw (v=velocity, f= frequency, w=wavelength) 2. Features of a wave model can be utilize to mark for the properties of sound 1. make that sound waves are vibproportionns 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 make up the medium, sound is a vibration of the medium. 2. Relate compressions and rarefactions of sound waves to the crests and troughs of transverse waves used to represent them A. Co mpressions 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 direct a maximum displacement upwards or in a positive direction.Trough The point of a wave where the particles of the medium have a maximum displacement downwards or in a negative direction 3. excuse qualitatively that pitch is think to frequency and volume to bounteousness 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 have a high amplitude you leave behind have a loud sound.When the frequency incr substitutes so does the pi tch. 4. Explain an call in as a verbal expression of a sound wave A. An hark back occurs when a sound wave is reflected eat up a cake and returns to the source. 5. Describe the principle of super ready and compare the resolveing 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 person shout, and then you get two people to shout, each at the same volume as the first person, the resulting volume bequeath be the sum of the two volumes. . Recent technological developments have allowed great use of the electromagnetic spectrum 1. Describe electromagnetic waves in terms of their speed in space and their wishing 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) electromagnetic waves travel at the speed of light, a continual pertain to 2. Identify the electromagnetic wavebands filtered out by the atmosphere, peculiarly UV, X-rays and gamma rays A.The Earths atmosphere provides a protective protection from harmful electromagnetic radiation. Fortunately this portion of the EM spectrum (UV rays, X-rays and Gamma rays) is filtered by the Earths atmosphere. Earths atmosphere filters out most of the electromagnetic waves except for visible light and receiving set waves. 3. Identify methods for the detection of various wavebands in the electromagnetic spectrum A. Radio waves are detected with radio pay offrs that are link up to aerials. Microwaves are detected with piezoelectric crystals. Visible light is detected by photoelectric cells. 4.Explain that the relationship between the intensity of electromagnetic radiation and distance from a source is an example of the inverse substantive law A. The strength of a symptom is proportional to the square of the distance from the source of that signal. This mover 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 used to put crosswise information A. Modulation is the process of conveying a message signal inside another signal that can be physically transmitted.With amplitude modulation (AM), the amplitude or strength of the mail carrier signal is varied, which corresponds to changes in the sound, while its frequency sticks constant. With frequency modulation (FM), the frequency of the carrier wave is altered according to changes in sound while the amplitude remains constant. 6. Discuss problems produced by the limited range of the electromagnetic spectrum in stock(predicate) for communication purposes A. There is only a limited range of wavelengths in the electromagnetic spectrum that can be used for communication purposes. 4.Many communication technologies use appli cation programs of reflection and refraction of electromagnetic waves 1. Describe and apply the law of reflection and explain the effect of reflection from a plane surface on waves A. aspect is the bouncing of a wave when it hits a surface or obstacle. admonitions of all types of waves follow the law of reflection. Angle of Incidence = Angle of Reflection The law of reflection states that the be given of the incident wave must fair to middling the angle of the reflected wave and the incident wave and the reflected wave must catch ones breath in the same plane.It is important to remember that the angle of incidence and the angle of reflection is calculated from the normal. The normal is perpendicular to the plane of reflection (e. g. a mirror). 2. Describe ways in which applications of reflection of light, radio waves and microwaves have assist in information transfer A. Reflection of light is used fiber optics and in CDs. Fibre optics allow for massive mensurations of inf ormation transfer. Reflection of radio waves are utilised when radio waves are reflected off the ionosphere. video recording and radio use this reflection to transfer information. . Describe one application of reflection for each of the following Plane surfaces Concave surfaces Convex 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 any reflected of the CD or not. Reflection of convex surfaces is used in security mirrors, where it goodns the handle of view. Reflection of concave surfaces is used in torches, where the rays of light travelling backwards are projected forward, for more brightness. It is besides used in beam dishes.The ionosphere reflects a percentage of radio waves sent up, back towards earth. This allows for selective information to be sent through the radio waves over long distances. 4. Explain that refraction is related to the velocities of a wave in co ntrary media and outline how this may result in the plication of a wavefront A. Refraction is the bending of light as it changes speed upon entering a medium with different optical density. 5. sterilise refractive magnate in terms of changes in the velocity of a wave in passing from one medium to another A. The refractive index of a medium is the change in velocity 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 uprightness A. 7. Identify the conditions necessary for jibe internal reflection with reference to the small angle A. The critical angle is the angle of incidence, which forms an angle of refraction at 90. If the angle of incidence is less than the critical angle then you exit have normal refraction, and if the angle of incidence is greater than the critical angle then you testament have total internal reflection. 8. Outline how total internal reflection is used in optical fibres A.Opti cal fibres work by having one medium coated by another medium with a lower refractive index. The angle that enters this is greater than the critical angle so therefore the ray of light bounces nearly inside and travels from one end to another, neer exiting the fibre. Therefore a light ray can travel through the wire. The ray of light never has an angle of incidence of less than the critical angle, so the ray never escapes the optical fibre. 5. Electromagnetic waves have potential 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 Energy in the Home 1. Society has become increasingly domestic energy dependent on electrical energy over the utmost 200 year 1. Discuss how the main sources of domestic energy have changed over time A. Th e first main source of domestic energy used by humans was fire, through wood, and then came domesticated animals, nobble and water, coal, coal gas, electricity, fuel oils, solar and lastly nuclear energy.These have positive from the start of human existence to now. 2. Assess some of the impacts of changes in, and increased entrance fee 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 Alternative motive sources can be used, such as solar or wind. 2. peerless of the main advantages of electricity is that is can be moved with comparative ease from one place to another through electric tour of dutys . Describe the demeanour of electrostatic pulls and the properties of the throw field of operationss associated with them A. An determination lens becomes electrostatically burgeon forthd when there is either a deficiency or excess of electrons. The two types of spud are called positive charge and negative charge. Electrostatic charges cause charged particles to move of change direction. Electrostatic charges create a field of charge. An electric field is a region in which a charged particle will experience a constrictfulness. 2. Define the unit of electric charge as the ampere-second. 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 latest of one ampere flows 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 flows (coulombs/ second or amperes) under the influence of an electric field A.Electric current is defin ed as the amount of electric charge aerodynamic 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 opposite direction of conventional current. 5. identify that current can be either direct with the net flow of charge carriers piti adapted in one direction or alternating with the charge carriers moving backwards and forwards sporadically A. AC current involves the oscillation of electrons due to an electric field that is eer 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, port adapted radios, lights in cars, and toys. 6. Describe electric potential contravention ( po tency) 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 difference changes at different points around a DC travel A. potential difference 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 around the term of enlistment. 8. Identify the difference between music directors and insulators A. -A conductor is a substance in which there are step down 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 protection as the ratio of voltage 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 durable the material the high the metro is. Cross sectioned 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 resistivity of that material. . serial publication and parallel circuits serve different purposes in habitations 1. Identify the difference between series and parallel circuits A. A Parallel circuit is a unappealing circuit in which the current divides into two or more paths in the first place recombining to complete the circuit. A series is a circuit having its parts connected serially Advantages of using 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. All devices receive the highest possible volta ge. 2.Compare parallel and series circuits in terms of voltage across components and current through them A. In a parallel circuit the voltage is the same throughout the whole circuit while the current is dissever between evenly throughout the circuit. In a series circuit the current is the same throughout the circuit while the voltage is split up 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 situated 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 diff erence between two points, so is must be placed in parallel so that it can measure the difference between before and later on 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, heating 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 circuits so there is enough power. 4. The amount of power is related to the rate at which energy is transformed 1. Explain that power is the rate at which energy is transformed 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 en ergy used depends on the length of time the current is flowing and can be calculated using Energy = 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 all(prenominal) 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 poles of shut off magnets when they are brought close together A. Magnetic fields are from north to due to the southwestward. When two bar magnets are brought close together the magnetic fields around their poles will produce a force between the two magnets. If two alike 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. alike(p) poles repel Unlike poles attract. 2.Define the direction of the magnetic field at a point as the direction of force on a genuinely 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 grasp would indicate at that point. 3. Describe the magnetic field around pairs of magnetic poles A. The magnetic field around pairs of magnetic poles is best described 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 light magnetic field they are well apart. . Describe the production of a magnetic field by an electric current in a slap-up current carrying conductor and describe how the right hand trance rule can determine the direction of current and field lines A. When current is passed through a conduct or, 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 multiplication 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. Safety devices are important in household circuit 1. Discuss the dangers of an electric snow from both a 240volt AC mains supply and various DC voltages, from appliances, on the muscles of the body A. There are several dangers when the muscles of the body are open to electric shocks. These are Pain receptors are usually activated. Involuntary condensing 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. Severe ru in are inevitable. Instant death often occurs. 2. Describe the functions of circuit breakers, fuses, earthing, recur insulation and other safety devices in the home A. Double Insulating flora by wrapping or encasing the electric components of an appliance with insulating material The insulating station 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 short darn of an alloy of lead and tin, connected in series with the devices that it controls. The fuse is intentional to melt when the current passing through it exceeds its threshold value. Circuit breaker 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 running(a) 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 typ ically travel at a constant speed 1. Identify that a typical journey involves speed change A. Motion occurs when an object changes its position relative to other objects or within some organise arranging.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 instantaneous and modal(a) 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 sender quantities in equations A. Scalar uantites have a range of magnitude but no direction examples include distance, speed and time. Vector quantities have a magnitude and a direction. Examples include velocity, force and displacement 4. Compar e instantaneous and average speed with instantaneous and average velocity A. Instantaneous speed is a scalar sum, on the other hand instantaneous velocity is a transmitter quantity. Average speed is also a scalar quantity and average velocity is a vector quantity. Average speed takes into account your whole journey, where as average velocity only takes into account the starting line and ending points. 5. Define average velocity asA. 2. An analysis of the outside forces on vehicles helps to understand the do of speedup and deceleration 1. Describe the motion of one body relative to another A. Motion occurs when an object changes its position relative to other objects or within some coordinate system. e. g. You are watching Coyote chase Road Runner. Road Runners velocity is 17 m. s east and Coyotes velocity is 15 m. s east. Road Runners velocity relational to you is 17 m. s east. Road Runners velocity telling 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 add vectors, to key out the accompanying 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 remote force to act in order to change the velocity of an object A. An object remains at rest, or in uniform motion in a straight line unless acted on by an out-of-door 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 half-baked 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 say by northwards 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, gravitational attraction, air resistance and clang to slow a car d own, and trust from the 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 Air resistance A.Friction examples are constantly seen throughout a normal day and it normally slows you down or helps change direction 6. Define average acceleration as A. 7. Define the terms mass and angle 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 acting on that mass. Weight 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 particle accelerator Pressing on the accelerator Pressing on the brakes loss over an icy patch on the road Climbing and descend hills Following a curve in the road A. 9. Interpret Newtons Second Law of Motion and relate it to the equation A. The net force of an 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. brighten force is defined as the vector sum of all forces.The net force is the resultant force of all individual forces acting 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 touch 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 u nderstanding motion . Identify that a moving object possesses kinetic energy 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 flexile materials as the result of their stretching or compressing. In an elastic collision, the EK after(prenominal) the collision is equal to the kinetic energy before the collision. Inelastic collisions result in the transformation of energy into other forms. It is usually lost to the environment in the form of heat or sound and is no longer in a useful form. . Define the law of conservation 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 impetus relates to the forces acting on the vehicle or the driver 1. Define caprice as Momentum is a measure of an objects tendency 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 force and time caprice is force applied over a period of time Impulse = effectiveness (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 reduce 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 just 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 Law of Motion is not apparent in many real being situations There is always some type of friction that will check 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 accompaniment of air bags and crumple zones to vehicles with respect to the concepts of impulse and momentum Air Bags and get onto 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. piteous Speed zones are in place because, the slower your velocity, the less momentum you have and the faster you can stop 4. Evaluate the effectiveness of some safety features of motor vehicl es 8. 5 The Cosmic Engine