Physics Dot Points Prelim

Physics computer program dot daub summary Nathan Kulmar 8. 2. 1. 1 refer the bureau trans take a hopulaations needful in unriv all in alled of the fol commencementing mobile tele telephony fax/modem wire little and television life armament is stored as chemical animation in the ph unrivaleds battery. Chemical aught is modify into electrical free zero to hunt down the phone.The microphone converts sound vital drag in to electrical postal code. Antanna converts electrical to electromag acquitic postcode to s oddment a siginal. The receiver speaker converts electric free pushing in to sound sinew. 8. 2. 1. 2 get a line vagabonds as a exile of energy disturbance that whitethorn occur in one, dickens or three dimensions, depending on the nature of the wave and the spiritualist The energy from waves may spread fall out as a disturbance in Dimension- push travels in a straight line from the source 2 Dimensions- qualification spreads out in a plane or surf ace 3 Dimensions- ability spreads out in to space surrounding the source in all channelizes 8.2. 1. 3 invest that mechanical waves bring a medium for propagation while electro mag last-placeized waves do not Mechanical waves assume a medium, solid, liquid or gas to transfer energy. Electro charismatic waves which put ont require a medium for transfer of energy. 8. 2. 1. specify and don the followe terms to the wave model medium, shimmy, amplitude, period, compression, r atomic number 18faction, c stay put, trough, transverse waves, longitudinal waves, frequency, wavelength, f number Medium is what isnt need for the electromagnetic spectrum to travel. Displacement the remoteness from the point of equilibrium to the wave Amplitude the duration to the point of maximum displacement Period age taken o complete a whiz wave length Compression an sphere of influence where partials ar pushed togetherRargonfaction point where a partial r all(prenominal)es its maximum displ acement vertically down c bothwhere the point where a partial reaches its maximum displacement vertically up Trough the point where a partial reaches its maximum displacement vertically down Transverse waves the command of travel is at expert leans to the cycles/ plump for (figure 2) persistentitudinal waves the program line of travel is tally to the oscillation (figure 1) Frequency the number of oscillations that pass a point in a second.V. remoteMissilesNight visibility gogglesSoft tissue treatment Microwaves overture MobilesSending info. Cooking Radio waves Antenna CommunicationAstronomy 8. 2. 3. 4 rationalize that the birth betwixt the intensity of electromagnetic actin nigh an early(a)(prenominal)wiseapy and distance from a source is an example of the inverse square faithfulness I? 1d2 The intensity of the electromagnetic irradiation is relative to 1 divide by the distance squared. As the waves travel further from the point of channel they spread out and b e answer less(prenominal) intense. I=k/d2 I=intensity k= changeless d= distance 8. 2. 3. chalk out how the prosody of amplitude or frequency of visible light, microwaves and/or radio waves send packing be hired to add knowledge Information is converted into a wave and then placed on a machinerier wave. It uses the properties of superposition principle to place the wave on to the elevator simple machinerier wave. Digital is make up of a series of ones and zeros. Digital encoding is made in to binary and are transmitted via light, microwaves, television waves and waves from the electromagnetic spectrum. on that point are two types of analogue transition one is AM. AM stands for Amplitude Modulation.This works by a using a broad(prenominal) frequency carrier wave which has the modulation signal placed on it. Frequency direct breathe the same but amplitude go off alternate. The other Form is FM. This stands for Frequency Modulation. A wave is frequency is elect as th e carrier wave and the modulation signal is placed on the carrier wave. Amplitude stays the same. 8. 2. 3. 6 discuss problems produced by the confine range of the electromagnetic spectrum available for communication purposes All EMR (electromagnetic radiation) will adjoin attenuation (reduction in intensity) as they pass through with(p) the atmosphere or any other veridical.As the earth is bombarded with UV radiation from the sun the ionosphere be grows missionary workd. This lav cause problems such as ghosting which is a double image on your T. V. screen. Also large portions of EMR are unable to be employ because they are too dangerous such as Gamma-rays and X-rays. Ultraviolet and visible are too difficult to produce and encounter too practically interference. full infrared and infrared also carry difficult because of impurities in visual fibbers will absorbed the light. Microwaves and T. V. waves require line of sight to be practical. . 2. 4. 1 expound and apply th e truth of comment and let off the effect of reflection from a plane surface on waves Electromagnetic waves may be reflected from a plane surface and they must(prenominal)(prenominal) obey the police of reflectivity Angle of incidence equals the angle of reflection Incident ray, reflected ray and standard must all be in the same plane. 8. 2. 4. 2 hound slipway in which applications of reflection of light, radio waves and microwaves stool assisted in entropy transfer Light is utilise in optical fibbers to transmit info.The light is reflected off the inside of the glass tube and atomic number 50 dis weight down multiple messages at the same snip in a iodin fibber. Radio waves are reflected off the ionosphere to that they arouse travel a womb-to-tomb distance. Microwaves send transitions to satellites where they are reflected back finished the atmosphere to earth. 8. 2. 4. 3 pull back one application of reflection Plane surfaces Mirrors. They allow people to car riage at their bodies without distortion. Concave surfaces Satellite dishes. They focus incoming rays to a single point called the focus and energised the signal at this point. Convex surface empennage vision mirrors.They allow a large issue of view in a grim area but will give the attestant a false scene of distance Radio waves being reflected by the ionosphere Radio waves are reflected off the ionosphere to provide a greater distance to which a listener fucking be from the source of the broadcast. 8. 2. 4. 4 inform that bending is related to the velocities of a wave in various media and limn how this may result in the parrying of a wavefront warp is the phenomenon where waves appear to bend as the waves pass from one medium to several(prenominal) other(prenominal). If wavefronts glisten a boundary at any other angle other than 90 than a permute of further will occur.If a wave goes from one medium to another and the stimulate is lower than it will bend towards the normal. If it goes into a medium where the speed is faster than it will bend apart from the normal. The waves bend because the incident ray first strikes the medium it belatedlys down and the rest of the ray continues at the same speed until it makes contact with the medium. It is the wavelength that qualifyings not the frequency. 8. 2. 4. 5 coif refractile superpower in terms of changes in the focal ratio of a wave in passing from one medium to another The refractive index is the ratio of the two wave velocities during the efraction. The refractive index is a measure of how much the light bends. 8. 2. 4. 6 desex Snells Law V1V2=sin isin r V1 and V2 are the speeds of the waves in wave in the antithetic mediums. Sin i is the angle of incidence and sin r is the angle of reflection. It is the relationship amongst speed, wavelength and angles of incidence refraction was determined experimentally by Willebrorod Snell and is known as Snells goodfulness. 8. 2. 4. 7 pick out t he conditions undeniable for total inborn reflection with reference to the life-sustaining angle If the critical angle is reached than the angle or reflection is 90.When the critical angle is exceeded than the light cant escape and total internal refraction occurs. The light must be travelling from a medium with a higher refractive index to one with a lower refractive index. 8. 2. 4. 8 outline how total internal reflection is employ in optical fibres Optical fibres are one application of total internal refraction. They are made of high purity glass, the central region is called the core and the outer region called the cladding. The cladding confines the light to the core and t accordingly must have a lower refractive index than the core.Once information is digitally encoded, at the transmitting end, the signal is converted from electrical energy to light energy and then transmitted on the optical fibre. The information is sent as a series of coded pulses of light. The pulse is either on or off. At the receiving end it is decoded. 8. 2. 5. 1 notice types of communication data that are stored or transmitted in digital form CD ROMs (Compact Disk Read-Only Memory) these discs store data in digitised form as picayune bits. They are read using a low power optical maser beam. They cannot be edited and are read up to now.They are fairly easily to read and can only store 8000Mbytes DVD (Digital Versatile Discs) these disks can hole 5 billion bytes of data, thus making possible the terminal of memory consuming movie length video and sound. GPS (Global Positioning Systems) this ecumenical outline uses a fleet of 24 satellites that transmit signals constantly. A GPS system, some hundred dollars, can interact with the satellite to pinpoint your latitude, longitude and altitude with in 50m. 8. 3. 1. 1 discuss how the main sources of domestic energy have changed over cartridge holder.The sources of domestic energy have changed rapidly over time * 50,000 BC control of fire cooking and heat energy * 10,000 BC domestication of wildcats animal power for outrage and ploughing. * 3,000 BC wind and water power travel boats and windmills * 1750 AD burning of coal begins to replace wood. Steam engines, trains, move, ships. * 1780-1800 scientific investigations of the properties of electrical energy. contradictory theories, scientific curiosity small amounts of energy in batteries. * 1830s obtain how to generate electricity using a dynamo (generator).Still used in scientific labs. * 1880-1910 a flood of inventions such as the light bulb, telephone, gramophone and radio were create with electricity. * 1950- all industrialized nations had become totally converted to electricity for domestic power. 8. 3. 1. 2 assess some of the impacts of changes in, and increased access to, sources of energy for a comm building blocky Some impacts of wedges in sources of energy are * The use of coal has had a particularly large impact on our society. * e mber burns tempestuous fires to make steel and other alloys. Steel major(ip) factor that lead to the industrial revolution. * Coal lead to the maturement of the steam engine. * Pollution and global warming was created. 8. 3. 1. 3 discuss some of the ways in which electricity can be provided in remote locations engross small generators that rotate a coil by a gasolene or oil motor. solar cells and wind generators are also used to convert sunlight and wind into electricity. 8. 3. 2. 1 cast the behaviour of static charges and the properties of the plain of operations associated with them * Two types of charges positive and prohibit Charges go away from positive, charges go towards negative * An electrostatic charge is a charge due to an redundancy or deficiency of electrons. * A remains with equal number of protons and electrons will be neutral. * Body has an excess of electron is negatively charged. 8. 3. 2. 2 dress the unit of electric charge as the ascorbic acid electr ic automobile charge is measured in coulombs the coulomb (c) is the SI unit of electric charge. 1 coulomb = 1c = 6. 25 x1018 charge = 1. 6 x1019 charge 8. 3. 2. 3 ready the electric field as a field of extract with a field strength equal to the lastingness per unit charge at that point E=FqE = magnitude of electric field (NC-1) newton per coulomb q = charge (C) coulombs F = nip (N) Newton 8. 3. 2. 4 define electric sure as the rate at which charge flows (coulombs/ second or amperes) under the influence of an electric field rate of flow is the rate at which charge flows (Csec. or Amperes) under the influence of an electric field. I= QT I = veritable Q= charge (coulombs) T= time (sec) 8. 3. 2. 5 distinguish that period can be either direct with the net flow of charge carriers moving in one statement or alternating with the charge carriers moving backwards and forwards periodically DC = direct realCharge moves in one direction Direct positive to negative movement AC = alte rnating original Charge moves back and fore periodically. Directions changes 50 times per second. 8. 3. 2. 6 describe electric potence contravention ( emf) in the midst of two points as the change in potential energy per unit charge moving from one point to the other (joules/coulomb or volts) Electric potential engagement ( potential drop) amid two points is the change in potential energy per unit charge moving from one point to another (joules/coulomb or Volts). . 3. 2. 7 discuss how potential difference changes amongst different points near a DC overlap Potential difference can vary at different points close to a circuit for example at that place will be different voltage drops across various resistors, light globes and rheostats which would be different to the voltage rise across the power pack. 8. 3. 2. 8 recognize the difference between conductors and insulators Insulators will not allow electricity to flow by them because they have a very high resistance.Conductor s have a very low resistance and therefore will allow afoot(predicate) to flow by them. 8. 3. 2. 9 define resistance as the ratio of voltage to current for a particular conductor V=IR V= Voltage I= Current in amps R= Resistance in ohms 8. 3. 2. 10 describe qualitatively how each of the following call fors the movement of electricity with a conductor Length Resistance is proportional to length the semipermanent a conductor the greater the resistance Cross sectional area larger the cross-section the lower the resistance.Temperature temperature increases ions vibrate change magnitude resistance. Material material of a conductor influences resistance copper is commonly used for folk wiring, gold or silver used when minimal resistance required. 8. 3. 3. 1 identify the difference between series and parallel circuits Series * in that location is only one current pathway. * Current is the same throughout the unscathed circuit * If a series circuit is broken at any point then the el ectricity cannot flow through it. * Current clay constant and voltage varies (VT=V1+V2+V3).Parallel * There is more then one current pathway. * All components have the same potential difference across them * In parallel, voltage remains constant and current varies (IT=I1+I2+I3). 8. 3. 3. 2 compare parallel and series circuits in terms of voltage across components and current through them Parallel Series VT= V1 = V2 = V3 VT= V1 + V2 + V3 IT=I1 + I2 + I3 IT=I1 = I2 = I3 8. 3. 3. 3 identify uses of ammeters and voltmeters Ammeters measure the flow of electrons through a point in the circuit.Voltmeters measure the potential difference between two points. 8. 3. 3. 4 explain why ammeters and voltmeters are connected differently in a circuit Ammeter cannot change the current being measured, must have minimum resistance, current must flow through the ammeter, moldiness BE PLACED IN SERIES Voltmeter measure the penitential difference (voltage) between two points in a circuit, PLACED IN r eduplicate CURCUITS, important that voltmeter has high resistance so that there is not affect on the circuit. 8. 3. 3. explain why there are different circuits for lighting, heating and other appliances in a mob In a house there are separate circuits for lighting, heating and other appliances so that appliances that require large amounts of current can still function without over-loading the circuit. If everything was on one circuit there would be too much current used and the wires would become hot and potentially cause a fire. 8. 3. 4. 1 explain that power is the rate at which energy is transformed from one form to another Power is defined as the rate at which energy is transformed from one form to another. watt=1 W=1J/s 1kW=1000watts P=ET Power ((Joules = watts (W)) = faculty (J) / time (s) 8. 3. 4. 2 identify the relationship between power, potential difference and current Power is the number of joules per second (watts), for every current (I in Amps), Voltage (v in volts) are dissipated. P=VI Power (Watts) = Voltage (V) x Current (A) 8. 3. 4. 3 identify that the total amount of energy used depends on the length of time the current is flowing and can be calculated using Energy=VIt Electrical energy (joules) = Voltage (volts) x Current (amps) x judgment of conviction (sec) P=VIPower (Watts) = Voltage (V) x Current (A) P=ET Power ((Joules = watts (W)) = Energy (J) / time (s) 8. 3. 4. 4 explain why the kilowatt-hour is used to measure electrical energy consumption rather than the joule 1kW. h is the energy used by a 1 kW appliance operating for 1 hour. Measuring in joule is a big inconvenient because 1 joule is a very tiny amount of energy. 8. 3. 5. 1 describe the behaviour of the magnetic games of bar magnets when they are brought close together Magnets have 2 different poles north and south. They can either be make or repel each other.Opposite poles attract, same poles repel. 8. 3. 5. 2 define the direction of the magnetic field at a point as the direc tion of drive on a very small north magnetic pole when placed at that point The direction of a magnetic field is the direction of draw off on a very small magnetic north pole placed in the field. The currents from the north pole more towards to the south pole. 8. 3. 5. 3 describe the magnetic field more or less pairs of magnetic poles line of products lines come out of the North and into the south. Field lines never cross. The magnitude of the field is indicated by the density of the field lines. . 3. 5. 4 describe the intersectionion of a magnetic field by an electric current in a straight current-carrying conductor and describe how the undecomposed progress grip rule can determine the direction of current and field lines The direction of the magnetic field is described by the right egest rule. Right hand grip rule Grip wire with right hand, thumb pointing in direction of conventional current, fingers will curl almost in the direction of the magnetic field. 8. 3. 5. 5 compa re the nature and propagation of magnetic fields by solenoids and a bar magnet * A solenoid is a coil of wire. When a current flows in the solenoid it produces a magnetic field most the coil which is similar to that of a bar magnet. * In a solenoid the field continues through the middle as parallel lines. * The direction of the magnetic field inside a solenoid is given by the right hand rule. 8. 3. 6. 1 discuss the dangers of an electric shock from both a 240 volt AC mains supply and various DC voltages, from appliances, on the muscles of the luggage compartment * The neuromuscular system runs on the movement of electrical changes. An electric current through the body has the effect to disrupt its normal function. A common response of your bodys muscles to an electric shock would be * Muscles suffer so you wont be able to let go. * Muscles peremptory the diaphragm cause it to clamp (cant breathe) * Heart muscle goes into fibrillation ( resigns powerful beating till center s realizes altogether) * Death * Human bodies can withstand ten times as much DC current as AC, AC operates on frequency (50-60 Hz) which is the same frequency our heart operates making AC significantly more lethal than DC. 50-100 mA are the lethal limits for electric shock. 8. 3. 6. describe the functions of circuit breakers, mix ins, earthing, double insulation and other safety devices in the home Circuit breakers they use an electromagnet to automatically break the circuit. Once the current exceeds the maximum value. Fuses they prevent overloading of circuits. They are made of a admixture with a low thaw point. They melt when the current through the circuit exceeds the wiring. They are usually contained in high melting point materials to avoid fires. Earthing they protect from shock. If an appliance has any metal exposes than it will have the outer cover earthed to protect shock.It works on the bases that there is less resistance through the wire rather than through a person. D ouble insulation house hold wiring must be covered by an insulator. Usually made of plastic ((polyvinylchloride, (PVC)) many another(prenominal) a(prenominal) have double insulating in case the sexual insulation melts when the metal gets to hot. 8. 4. 1. 1 identify that a typical journey involves speed changes In a typical car journey, a car may travel at different speeds, accelerate and decelerate, changes direction and stops therefore although there is an average speed for the entire journey, the vehicle does not travel at a constant speed. . 4. 1. 2 distinguish between scalar and sender quantities in equations scalar quantities are those that specify size (magnitude), but not direction. Vector quantities are defined by both size (magnitude) and direction. Vectors Scalar exponent people Velocity Speed Displacement Distance quickening Work nervous impulse Energy Magnetic Fields Power Electric Fields Time 8. 4. 1. 3 compare instantaneous and average speed with instantaneous and average velocity Average Speed = Distance/ make out Time Instantaneous Speed is the speed of an intention at a particular instant of time.Velocity (v) is the time rate of change of the displacement. It is a vector it requires both size and direction. It is speed with a direction. Displacement (s) is distance in a given direction. Instantaneous velocity is the velocity at a particular instant, the speed and the direction. Average Velocity is displacement/time. 8. 4. 1. 4 define average velocity as vav= ? r? t r = s = displacement. Average velocity= change in displacement/ change in time. 8. 4. 2. 1 describe the enquiry of one body relative to another Motion occurs when an object changes its position relative to other or some co-ordinate system (a frame of reference).If a change in direction occurs thorough vector qualities, must be dealt with as vectors. 8. 4. 2. 2 identify the usefulness of using vector diagrams to assist solving problems Vectors qualities have magnitude and direction. Adding Vectors Draw the first vector. Draw the second vector starting from the end of the first. The resultant vector is the line joining the beginning of the first vector to the end of the second. 6km 8km 10km a 6km 8km 10km a Subtracting Vectors V1 V2 = switch over in VChange V = V (f) V (i) V1 -V2 V1 V2 V1 -V2 V1 V2 Change = Final Initial Change V 8-(-10) = 18 -10m/s 8m/s -10m/s m/s 8. 4. 2. 3 explain the need for a net away rage to act in order to change the velocity of an object powerfulnesss can internal or external to a system but only the external force backs can affect the crusade of the system. Net force = sum of all forces. Change in velocity the object must accelerate. An object will remain in constant accomplishment (rest or 0 velocity) unless an unbalanced force acts on the object. To accelerate there must be an outside force acting (Newtons 1st law). Newtons first law states that A body continues in its state of rest or changeless velocity unl ess acted upon by an unbalanced force. . 4. 2. 4 describe the actions that must be taken for a vehicle to change direction, speed up and slow down acceleration is defined as the time rate of change of velocity. Acceleration refers to Speeding Up this can be done by using the accelerator Slowing Down this can be done by using the cars brakes Changing Direction Using the steering wheel 8. 4. 2. 5 describe the typical effects of external forces on bodies including skirmish between surfaces noticeise resistance There are a number of external forces working on a car and these take Friction with the Road standard atmosphere Resistance The weight of the carFriction is a force that we encounter everyday in everything we do. Friction is a force that evermore opposes motion. Friction arises when two different materials are in contact with each other. The tires make contact with the road surface and as a result there is friction. This means that the vehicle has traction and does not si mply slide. Air Resistance is a form of Friction. As a vehicle moves through the air the two materials, the vehicles body and the air, move past each other. Air resistance limits the speed of the vehicle but it can be minimize by designing a vehicle so that it is aerodynamically shaped. . 4. 2. 6 define average acceleration as vav= ? r? t therefore vav=v-ut Acceleration is a change in velocity over a plastered time period. It can be positive or negative. v= last-place velocity, u= initial velocity, t= time taken 8. 4. 2. 7 define the terms band and weight with reference to the effects of gravity Mass Is the measure of the amount of matter in an object Measure of in application (resistance to acceleration) In babelike or the effects of gravity Measured in grams. metric weight unit Is the force of gravity on an object. On earth weight is the stool x 9. 8 Dependent on the amount of massMeasure of the gravity and force on an object Measured in Newtons. 8. 4. 2. 8 outline the forces involved in causing a change in the velocity of a vehicle when Coasting with no pressure on the accelerator Friction with the Road Air Resistance Force Pushing car along Pressing on the accelerator The driver is supplying more discharge to the engine. This allows the engine to apply a greater force on the wheels and hence make the car speed up. Velocity and acceleration acting in the same direction. Pressing on the brakes Increasing the friction between the brake pads and the metal discs making it harder for the wheels to turn.Velocity and Acceleration acting in different directions. Passing over an icy patch on the road There is less friction and the wheels cant get as much grip so they may slide. The car will move at a constant velocity until acted upon by an external force. Climbing and descend hammocks Friction Air Resistance The cars weight causes it to slow down when difference up the hill and speed up when going down the hill Following a curve in the road Centripetal forc e is causing the car to accelerate as the velocity is changing owing to the change in direction. 8. 4. 2. interpret Newtons Second Law of Motion and relate it to the equation F=ma F= Force in Newtons m= mass a= acceleration 8. 4. 2. 10 identify the net force in a wide variety of situations involving modes of beguile and explain the consequences of the application of that net force in terms of Newtons Second Law of Motion The acceleration of an object is proportional to the unbalanced force acting on it and is inversely proportional to the mass. The consequences of net external force acting on a model of transport are acceleration, deceleration and a change of direction in motion.Centripetal force (circular motion) The force causing the turning is always towards the centre of the circle. Force (centripetal) = mv2/ R R=radius, V= instantaneous velocity, M= mass 8. 4. 3. 1 identify that a moving object possesses kinetic energy and that work done on that object can increase that energy energizing Energy is the energy an object possesses because it is moving. Kinetic energy is dependent on the mass and the square of the velocity of the body as indicated by KE=12mv2 E= kinetic energy (joules) M=mass of the object (kg) V=velocity (m/s)Work (W) is done when a force (F) is move through a distance (s). Work is the product of a force and the distance moved in the direction of that force. W=Fs. Work transfers energy through the motion of a force. When work is done, energy is required. W = Change in Kinetic energy 8. 4. 3. 2 describe the energy transubstantiations that occur in collisions In collisions objects exert forces on each other. Collisions can be either springy Non-Elastic Elastic Collisions If in a collision, kinetic energy is conserve, the collision is say to be elastic.An example would be when Gas molecules collide with each other and with the walls of their container as kinetic energy is not decreased. Inelastic Collisions In inelastic collisions, kinetic energy is not conserved. Some of the Kinetic energy is transformed into other forms of energy such as heat and sound. If the colliding parts junction together, the collision is inelastic 8. 4. 3. 3 define the law of conservation of energy In all types of interactions, both elastic and inelastic, total energy is conserved. Energy cannot be destroyed only can be changed from one form to another. . 4. 4. 1 define caprice as p=mv pulsing= mass (kg) x velocity (m/s) Unit of pulsing= kilogram-meter/sec To stop a moving object, forces must be applied and the forces relate to two factors, the mass of the object and the velocity of the object. The time rate of change of momentum is proportional to the resultant force and acts in the direction of the force. Always conserved Vector quantity 8. 4. 4. 2 define impulse as the product of force and time pulse = F (force) x t (time) whimsey = change in momentum Impulse = Ft = mv mu mv = final momentum u = initial momentum The unit of Impulse i s N. s which is the same as the Unit of momentum= kilogram-meter/sec (kg. m/sec) 8. 4. 4. 3 explain why momentum is conserved in collisions in terms of Newtons Third Law of motion Force (action) = Force (reaction) Conservation of Momentum The total momentum of a system is always the same unless the system on by some external force. P ( beforehand) = P (after) m1u1+m2u2= m1v1+m2v2 This equation shows that the vector sum of the momentum of the objects before collision equals the vector sum of the momentum after collision.Momentum is conserved only in isolated systems (those free from external forces). The Law of the Conservation of Momentum can be stated as In interactions between objects, momentum is conserved in an isolated system. 8. 4. 5. 1 define the inertia of a vehicle as its tendency to remain in uniform motion or at rest Newtons 1st law Inertia Tendency of any object to resist any change in motion. E. g. when a car stops suddenly, the objects and people in the car remain in the current motion unless acted upon by an external force such as a seatbelt. 8. 4. 5. discuss reasons why Newtons First Law of Motion is not apparent in many real world situations Common experience is not apparent in Real World Situations as the driver of a car still needs to depress the accelerator to move at a constant rate because of friction between the car and the road. 8. 4. 5. 3 assess the reasons for the foot of low speed zones in built-up areas and the addition of air bags and crumple zones to vehicles with prise to the concepts of impulse and momentum Introduced low speed zones into built areas to reduce the speed of drivers as the faster you are moving the more damage you do in a collision.Crumple Zones were introduced so that the front and rear end of the car should crumple in a collision which increases the time it takes for the car to come to rest so the forces are lessened. Air Bags were introduced which provide a cushion and takes the impact out of a collision. 8 . 4. 5. 4 evaluate the effectiveness of some safety features of motor vehicles Seat Belts They are effective in limiting the effect of inertia when a vehicle breaks suddenly. It absorbs a lot of the force of a collision. Airbags Air Bags were introduced which provide a cushion and takes the impact out of a collision.Crumple Zones Crumple Zones were introduced so that the front and rear end of the car should crumple in a collision which increases the time it takes for the car to come to rest so the forces are lessened. 8. 5. 1. 1 outline the historical development of models of the Universe from the time of Aristotle to the time of Newton Plato planets move in world(a) orbits around the earth (geocentric) Eudoxus maintained Platos concepts of spherical motions, complex arrangements of circular motions Aristotle developed Eudoxus model to 53 spheres. Aristarchus The sun is in the centre (heliocentric) with everything orbiting around it and epicycle moments to explain planetary movem ents Earth must rotate on its axis, so it appears that everything moves around us. Ptolemy believed in geocentric universe, stars existed on a sphere which revolved every 24 hours, earth is a sphere and at rest, motion of sun and plants moved in perfect circles. Copernicus heliocentric universe, sun was the centre and planets orbited the sun in fixed circular motions, earth traveled around the sun in 1 year and spins on its axis every 24 hours. Galileo first to use a telescope, supported the heliocentric intellection of Copernicus, worked on gravitational guess disproved Aristotle concepts of the motion. Sir Isaac Newton from work on motion realized that a forcer must be acting on an object such as the moon, law of universal gravitation, this explain where things stayed in orbit, since the time of Newton the heliocentric model was accepted. 8. 5. 2. 1 outline the stripping of the enlargement of the Universe by Hubble, following its earlier prediction by Friedmann horse parsl ey Friedman predicted that the universe was expanding.The predictions rose from calculations based on champions, general theory of relativity. Edwin Hubble designed a new and a bigger telescope that leads to the discovery of the red shift proving that the universe is expanding. A red shift corresponds to a shift to the lower frequency (longer wavelength). This indicates that the light source, the galaxy is moving away from us. All galaxies show this effect indicating that the universe is expanding. 8. 5. 2. 2 describe the transformation of radiation into matter which followed the Big Bang After the temperature had dropped enough.The energy began to be converted in to matter. Hydrogen atoms formed from protons and electrons. 8. 5. 2. 3 identify that Einstein described the equivalence of energy and mass E=mc2 E= energy (Joules) m= mass (kg) c= speed of light (3 x 108 ms-1) 8. 5. 2. 4 outline how the accretion of galaxies and stars occurred through Expansion and temperature reduction of the Universe The cooling of the universe allowed the formation of matter. This began to overwhelm the radiation Subsequent loss of particle kinetic energyAs the temperature fell this resulted in a loss of kinetic energy (as temperature is the measure of average kinetic energy of the particles) Gravitational attraction between particles Loss in Kinetic energy meant that the increased gravitational force between particles took effect Lumpiness of the gas cloud that then allows gravitational return The greater density of areas of the gas clouds allowed gravity to begin 8. 5. 3. 1 define the relationship between the temperature of a body and the dominant wavelength of the radiation emitted from that body The hotter the star the shorter the wave length.Hot star short wave length, more energy. low temperature star long wave length, less energy 8. 5. 3. 2 identify that the surface temperature of a star is related to its colour Red Long wavelength Orange Yellow White blue- white S hort wavelength The hotter the star gets the more it will shift towards the blue end of the spectrum and thus the shorter the wavelength. 8. 5. 3. 3 describe a Hertzsprung-Russell diagram as the graph of a stars luminosity against its colour or surface temperature In the Hertzsprung-Russell diagram a stars surface temperature and luminosity ( brilliantness) are plotted against each other.This is because there is a relationship between the two. 8. 5. 3. 4 identify energy sources characteristic of each star group, including Main Sequence, red giants, and white dwarfs Star group open fire Characteristics Main sequence H then He They are from the top left of the Hertzsprung-Russell diagram to the bottom right. This shows a trend of hot and bright to cold and dull Red giants H then He In the upper right corner of the Hertzsprung-Russell diagram and are bright but cold White dwarfs C and O ions Bottom left of the Hertzsprung-Russell diagram. They are very hot but dim and small. 8. 5. 4. 1 identify that energy may be released from the nuclei of atoms Light atoms like H will fuse together at extreme temperatures to for stable atoms. This produces energy. Uranium on the other hand has very unstable nuclei and will break down by emitting energy or partials randomly. That may be in the form of ? , ? or gamma rays. 8. 5. 4. 2 describe the nature of emissions from the nuclei of atoms as radiation of of import ? and beta ? particles and gamma ? rays in terms of ionising power penetrating power effect of magnetic field effect of electric fieldRadiation Ionizing power crisp Power Effect of Magnetic Field Effect of Electric Field Alpha Particle Very high Strong Low a few cm in the air Affected according to right hand palm rule Limited very small important Particle Less than AlphaWeak amplyer than Alpha thin sheets of lead handsome Large Gamma Ray Less than BetaVery Weak Very High Several cm of lead Zero Zero 8. 5. 4. 3 identify the nature of emissions reaching the Earth from the Sun Solar wind consists of a stream of ionised particles, mostly protons and electrons that flow from the sun in all directions at speeds of about 400 km. -1. The source of the wind is the suns hot corona the outer atmosphere of the sun extending a distance of a few solar radii into space. Most of the corona consists of vast arches of hot gas solar flares that are millions of kilometres in length and are caused by the suns magnetic field. The Solar wind comes from regions called coronal holes, regions of cooler, less dense gas. As the sun rotates there is a periodic vicissitude in Solar wind exertion every 27 days. The Solar wind is responsible for pushing the tail of comets away from the sun. 8. 5. 4. 4 describe the particulate nature of solar windSun spot cycle is a pattern of increasing and decreasing sunspots. Sun spots are a down(p) spot on the sun with lower temperatures and intense magnetic activity. Cycle is between 7-13 years. Two types of emission reaching Earth from the sun electromagnetic radiation and solar winds. Earths atmosphere and magnetic field shelters as from theses emissions. The sunspots themselves last for several days although larger ones may last up to a few weeks. The number of particles and their velocity increases following sunspot activity and solar flares meaning that the solar wind is greater in the time of maximum sunspots. . 5. 4. 5 describe sunspots as representing regions of strong magnetic activity and lower temperature Sunspots are relatively cool areas (4500K), with magnetic field strengths some thousands of times stronger than the Earths magnetic field, that appear as dark imperfections in the photosphere. They result from the penetration of magnetic field lines through the photosphere and are 8000km across. Except for the smaller ones, all sunspots have a dark inner region the umbra where the magnetic field is strongest surrounded by a less dark region the penumbra where the magnetic field is weakest .