As Fast As You Can Essay Example Essay Example

As Fast As You Can Essay Example Paper As Fast As You Can Essay Introduction Vector quantity – they have magnitude (size/speed/unit/distance) and directionSpeed – how fast you’re goingVelocity – speed in a given direction (vector quantity)Displacement – the distance in a given direction (vector quantity)Speed cameras work by taking two pictures, and then used formula (speed = distance/time)Acceleration – how quickly velocity is changing. Change speed or change in direction.Acceleration = Change in Velocity (two units taken away from eachother)/Time TakenGraphs: the gradient is the acceleration. Straight line is steady speed, straight line going up is steady acceleration, and curved line going up is increasing acceleration.Balanced force means steady speed (which could be stationary object).Unbalance force means acceleration in the side that has the most force acting on it.When something has no force applied to it, it will stop because of friction. (If you don’t accelerate a car it will stop eventually). To avoi d resistance or drag from things they must be streamlined so that the resistance can travel over.Terminal Velocity – maximum speed that something can reach with that force applying on it. Example: when car starts, it has less resistance, as time goes by: resistance equals the acceleration which means the car has reached its terminal velocity.Rules: Balanced forces: it’ll stay at same speed Unbalanced force (resultant force): object will accelerate in direction of force Bigger force; more acceleration. Bigger force needed to move big massForce = Mass x Acceleration Example: Forced needed for 12kg at 5m/s is 60NIf you apply a force on a wall if exerts the same force on to you.The distance a car needs to stop is calculated by: Thinking and Braking Distance.Thinking distance: Speed Mentality; drugs, tired, alcohol Visibility; rain, snow, dirty windows, darknessBreaking Distance: Speed Weight; more force must be applied to stoop a heavy car Brakes; shit breaks take longer t o stop Grip; road surface, weather, tyres: if grip is shit it’ll take longer to stopMomentum (kg m/s) (vector quantity) = Mass (kg) x Velocity (m/s):More mass/velocity, the more momentum: momentum is force of something hitting something else. Force causes change in momentum.Force acting = Change in Momentum (kg m/s) / Time Take for ChangeCars are designed to slow people down over a longer time when they crash (longer for change in momentum): Crumple Zone – bonnets take a long time crumple Seat Belts – stretch so there is less force acting on chest Air bags – slow you downRoller coasters and RelativityEnergy is always transferred; Food enables us to move (Chemical – Kinetic)Work Done = Force x DistanceKinetic Energy (moving) = 1/2 Mass x Velocityà ¯Ã‚ ¿Ã‚ ½Energy’s unit is Joules.Potential Energy = Mass x Grams x HeightEnergy Conservation – Using other energy to save fossil fuels and save the world.Principle of Conservation of Energy – energy can never e created or destroyed: only converted from on to another.Energy is only useful when you transfer it from one form to another.When something falls, the potential energy is converted to kinetic energy:Kinetic Energy gained = Potential energy lostPower is the rate of doing work. So Power = Work done / Time TakenPower measured in watts or j/s (same thing)Circular force – velocity is always changing (accelerating). A force acting toward the centre of a circle is called a centripetal force.Putting Radiation to UseIonising – losing/gaining electrons, three types: Alpha (Helium Nuclei) – Big, Heavy and Slow Moving, + Charge – Strongly Ionising: Doesn’t Penetrate far into materials, stopped by PAPER Beta – Small, negatively charged, in between, moderately ionising and penetrating, stopped by ALUMINIUM Gamma – weakly ionising but can penetrate far into a material, stopped by LEADBackground radiation is all around us f rom: Everything; from unstable isotopes: food, buildings and rocks Space: Cosmic rays from the sun (earth atmosphere protects us from that) Humans; Errors like nuclear explosions and wasteBackground radiation can change depending where you are: High altitude: you are closer to cosmic rays Underground mines: because of the rocks down there Homes; some are built over or by granite which releases radiationRadon gas causes: lung cancer (ventilation systems can stop)Atoms: nucleus has most of the mass (still tiny) and protons and neutronsAlpha has 2+ chargeBeta has 1- chargeGamma waves have no chargeIsotopes – different forms of same element (different amount of neutrons), only a few stable ones. Unstable ones decay into other elements (and give out radiation on the way)You can tell when the unstable isotope atoms will decay, it’s random. Nothing affects decay.Radiation decreases over time.Half-life is the time taken for half of the reactive atoms to decay. Can’t do full because it takes too long.If half life falls quickly it has short half-life.How to work out half-life: Atom A’s activity is 500cmp (counts per min). 1 hour later it’s 125cmpThis shows it has two half-lives in hour, so 1 half life is 30minsHalf-life graphs always go down in a curve. G-M tube and counters are used to measure half life over time (multiple readings).You need to take away background radiation from every reading.Ionising Radiation Uses: Smoke detectors: alpha radiation placed next to electrodes a current flows, if smoke appears it absorbs radiation and stops current which sets off alarm Tracers in Medicine – check if things around the body are taking things as they should be. There will be a strong reading where the body isn’t doing something it should. Never use Alpha rays for body (they have longer half lives) Radiotherapy – high dose of gamma rays kill humans cells, so they can kill cancer cells. Food and medical supplies are exp osed to high dose of gamma rays which kills of microbes. Doesn’t use temperature which means it doesn’t damage food. Gamma rays need to have long half life so it doesn’t need to do it too often.Knowing half life and how much radioactive isotope left in specimen you can work out how long it’s been around.Carbon-14 makes up 1/10 000 000 of anything but when it dies, it starts to decay. It’s half life is 5730 years.So if a body was found with 1/80 000 000 Carbon-14 you could work out how long it was alive by:1/10 – 1/20 – 1/40 – 1/80 : Shows it has three half-lives. 3 x 5730 = whateverCarbon dating is uncertain because: Assumes same amount of carbon in air All living things take in same proportion of C-14 Substances haven’t been contaminated by recent carbonsBeta and Gamma causes most damage outside body because it can damage cells insideIf alpha gets in it can damage body a lot because it collides a lot with cells.Precauti ons that should be taken with radioactive things: No skin contact (tongs) Arms length – keep away from body Don’t look right at it Use lead boxPower of AtomsEinstein said that mass is a form of energy. Nuclear fission is proof of that.Nuclear Fission – The splitting up of uranium atoms. Uncontrolled releases of energy = bomb.Controlled (chain reaction):1. Slow moving neutron is fired at uranium.2. The neutron gets absorbed3. This makes the uranium unstable which causes it to split4. The uranium also gives off neutrons that can be used to hit other uranium particles (back to 1)The lost mass (the neutrons) are converted into energy which means Einstein was right.Nuclear mass gives out much more energy than chemical ones: why their used in bombs.The daughter nuclei (the result of the splitting in uranium) is radioactive and they are not stable (too many neutrons. They become stable by transforming neutrons in protons (in the process beta particles are given off). T hey keeping doing this until they become stable (called decay series)Nuclear Power Stations work like this: In nuclear reactors, controlled chain reaction takes place where uranium is split up, this gives off a lot of heat energy. The heat is used to boil water to drive a steam turbine Nuclear (Uranium Reactor) – Heat (Boiling Water – Kinetic (Turbine) – Electrical (Generator)Inside Reactor: Neutrons added to start splitting, daughter nuclei collide with other atoms causing temperature to rise, the Co2 which is pumped in carries away the heat energy which is used to turn water to steam (which powers the turbine)Nuclear Power Advantages: Clean; doesn’t release as much C02 into environment (which stops green house effect) Can create a lot of jobs in area Nuclear fuel is cheap (uranium)Nuclear Power Disadvantages: Overall cost is high (building power plants and getting rid of waste) Waste is radioactive so it could damage human cells if leaked (have to put d eep in the ground with metal containers and surrounded with concrete Dismantling nuclear plants takes decadesNuclear Fusion – the joining of small atomic nuclei. Opposite of Fission; it combines two light nuclei to make larger nucleus. Fusion makes more energy than fission. Fusion doesn’t leave much waste behind and hydrogen (by-product) can be used as fuel afterward.Problems: Fusion needs temperature of 10 000 000à ¯Ã‚ ¿Ã‚ ½C and really high densities. No material can stand that temperature so reactors are hard to make. You also have to keep the hydrogen (used as neutrons that are added) in a magnetic field. More power needed to produce conditions than reactor can make.Static electricity is charges that are not free to move about. This causes them to build up in one place and often ends with spark or shock when they do move.Static electricity is caused by friction: when two insulating materials rub eachother; electrons will scrap off one and go to another. This leave s a + and – on each one.Positive charges can not move. They are created by electron going elsewhere.Opposite charges attract. The larger the build of charges, the larger the shock/spark.Good uses of SE: Fingerprinting: fine dust is brushed over ridges of finger print (gives an image of finger print) then electrostatic dust lifter is used to lift dust and then a highly charged film pressed on to dust which are attracted to it. This leaves an impression on the film Laser Printing: A laser passes over the drum inside a printer, giving it a pattern of charged dots. The toner picks up the drum whenever a dot is there. The dots of toner then put onto the paper to make up words and pictures.When synthetic clothes are dragged over eachother, they static charges on both parts which causes a attraction. Sparks occur when they rearrange themselves. Also happen with car seats but shock happens when you touch metal outside.Lighting – rain drops and ice bump together which knocks of electrons. The electrons go to the bottom and then they build up and a huge voltage is given off.Aircraft Fuelling: when planes are being fuelled, the fuel gains a – charge from the pipe and the pipe gets + charge which could explode. You have to attracted metal strap so the electrons are conducted away. As Fast As You Can Essay Thank you for reading this Sample!

Photography Aperture and Shutter Speed Essay

Photography Aperture and Shutter Speed Essay Photography: Aperture and Shutter Speed Essay Camera Settings: Step 1: Never use the Auto (P) function on the camera ï Å  Three critical components to taking a photo – 1) ISO setting 2) Aperture 3) Shutter speed Always try to use A (aperture), TV (shutter speed) or M (Manual) settings on your camera. For all three you first need to set your ISO. ISO: Best way to think about ISO is in terms of the amount of ‘noise’ in a picture (or grainy pixels). A low ISO setting e.g. 100 will give you the lowest amount of noise and thus the highest quality image. A high ISO e.g. 4,000+ will give you more grain. The high-end cameras will still provide excellent quality at very high ISOs, and sometimes, especially with a black and white, the grainy look can be what you wish for anyway. Using a high ISO is good when you want to avoid using a flash but you are inside a building or if it is darker outside. You can retain a low ISO if you reduce the shutter speed but try to avoid a shutter speed lower than 60 as if the camera is hand held it will introduce camera shake (obviously if you use a tripod, go as low as you like with shutter speed) Suggest, switching to M, and then create levels of darkness inside and try out the different ISO settings until you understand what your camera will achieve at the different levels, in different conditions. Generally speaking for hand held photography – Bright sunny day = 100 ISO Cloudy day = 400 ISO Inside = maybe 600/800 Evening or in dark churches etc. = could be 2000 plus Once the ISO is set†¦ Aperture: Switch the camera to A – this means aperture priority! Therefore, if you choose an aperture setting (numbers from 1.5 – 22 usually, depending on lens used), the shutter speed will change automatically according to the light conditions and ensure that you have the correct exposure. (meter reading – there is a line on your camera screen with 0 in the middle. You aim to get a middle reading. If the arrow goes above 0 it indicates that some of the picture is over exposed, or if under 0 it is under exposed) There will be times where you will actively select an over or under exposure but I will comment on this later. Aperture numbers – there are more technical explanations that what follows but the general rule is a low aperture number or WIDE aperture as it is correctly put e.g. 1.5 / 2.0 etc. will provide part of the picture in detail and the rest as a blur. You can aid this process by introducing distance between the subject and the background. The more distance between, the more blurred the background will be at wide aperture settings. Also, if you then get close to your subject e.g. a coke bottle, with a wide setting, you will only get part of the label in focus. If you steadily back away, more of the bottle will come into focus. The flipside, is if you have a high number e.g. 18 / 22 (NARROW aperture), then all of the picture will be in focus and there will be no blur. NOTE: Lets say the subject is where the two lines cross. Your aperture number tells the camera how much either side (front and back) of the subject is to be in focus. Therefore, if you are taking a landscape picture, you do not need to focus on the horizon. Focus on something in the middle and with a narrow aperture, the front and back of the middle will then be in focus. Shutter Speed: Change the setting to TV (might be S on the camera too?) This now gives the shutter speed the priority! Select your shutter speed and then the camera will automatically change the aperture to ensure a correct exposure. I use this function less often, but broadly speaking, if you are taking pics of kids running, or cars driving past and you want them in sharp focus then 1/700 or higher is effective. For static objects, then its about how well you hold your camera (and what you want your other settings to be) but I’d advise never going lower than 1/60 without a tripod.