Physics of Collision - Term Paper Example

Task 3: ERT – Physics of Collision Location: Physics Year: 11 Semester: 3 Teacher: Unit: Physics of Collision You must adhere to the school assessment policy. This cover sheet must be attached to your assignment. Assignment Issued: Draft Checked: Discussion Board Checked: Due Date: Assignment Details Centre of gravity Raising the centre of gravity of a vehicle makes it unstable and therefore it can easily topple when a slide oppose force is applied against it. This is because, the centre of all forces acting on the vehicles are high above the base thereby making the vehicle and prone to accidents. Centre of gravity can be raised when the vehicle is packed beyond its carrying capacity, in Rollovers, SUVs, people carriers, and minivans, all of which have a higher centre of gravity than standard passenger cars. Therefore vehicles mainly SUVs, pickup trucks and vans that are more susceptible to rollover, should be produced with a lower centre of gravity and improved suspension with stability control well connected to its anti-lock braking system to minimise the risk of rollover. (Dolman, 1989) A "factor” in the context of collision is a circumstance contributing to the occurrence of an accident and therefore, without this factor, the accident would not have occurred. Equipment Failure Loss of brakes, tire blowouts or tread separation, and steering/suspension failure. Brakes - older drum braking systems fade when hot. Anti Blockier System brakes prevent the wheels from locking up during emergency braking maneuvers. Dual-circuit brake systems have made brake failure an unlikely because when one side of the circuit fails, the other side is effective to stop a vehicle. Disc brakes, found in modern vehicle, are more effective and help to avoid many accidents that could otherwise have occurred. (Sera, 2000) Tires - bias-ply tires are not safer. Radial tires are safer but need attention regularly. Under inflation, is the main cause of tire failure and this may be a great risk for road accidents. Worn-out tires pose great risk of road accidents and can also lead to tire failure because of the improperly balanced tires. Steering & Suspension - suspension keeps tires in contact with the road in a stable and manner and steering enables the driver to go around road obstructions and shun potential accidents. Steering or suspension system failure is catastrophic, especially at high speeds. (Toora, 2000) Roadway Design – poor roadway design is a major cause of road accidents because did not put into consideration road barriers, utility poles, railroad crossings, and guardrails to their current high level of safety that are key if road carnage has to avoid. Proper guidelines should be provided to road engineers to ensure quality in construction coupled with design flexibility to suit local conditions. Such flexibilities include: Hazard Visibility-consist of intersections, school zones, bends, merging lanes, livestock or pedestrian crossings, and crests. Others include road construction, accidents, parked or disabled vehicles, wild animals, traffic jams. Roadway Surfaces – use of single surfaces that does not take into consideration the environment, traffic volume, traffic speed, and location of the roadway. Blurred road markings invisible to the drivers and therefore they are not able to know about their ability to pass safely the location of the roadway in inclement weather, where road surface ends. Traffic Control Devices – lack of Traffic light signals, speed limit signs, yield and stop signs, school & pedestrian crossings, turning lanes, police surveillance cameras, and traffic circles or roundabouts and there, drivers are left to control themselves and this increases the risks of accidents. Behavioural Control Devices - limit ability of a vehicle to travel, including crash barrels, speed bumps, pedestrian islands, raised medians, high curbing, guard rails, and concrete barriers. Traffic Flow - lack Interstate highways which are safest roads as the flow of traffic is in one direction easing traffic flow in city. Rural two-lane roadways that are dangerous because of a high occurrence of head-on collisions and the problem faced by impatient drivers’ while overtaking Roadway Identification Signs - lack of road signs and therefore someone without a detailed map to travel from one place to another may end up causing accidents as he tries to consult the passersby on the possible direction he has to take. Proper roadway Identification Signs gives advance notice of intersections, hazards, destinations, route numbers, and points of interest, mileage estimates, and street names. Weather conditions that may aggravate existing hazards and create new road surfaces Head -on collision of two cars. When car A collides with car B, and a assuming that car A and car B are mirrors of each other, the two cars collide with each other going at the same speed but opposite directions. According to the conservation of momentum, the two cars come to rest. The mass of the two cars is the same and the force exerted on car A and car B is identical. Force is a vector quantity but the kinetic energy is a scalar quantity, calculated as K = 1/2mv2.each car therefore has kinetic energy K before collision but at the end of the collision, the total kinetic energy of the system is 0. Since the is inelastic collisions, kinetic energy is not conserved, but total energy is conserved, therefore, the kinetic energy lost in the collision has to convert into some other form . The total energy released during the collision is 2K.the crash is therefore more energetic and brings more distortion to both cars. The accident is therefore more fatal in head-on collisions. (Dolman, 1989) Momentum is proportional to the speed while kinetic energy (= ½mv2) is proportional to the square of the speed and therefore velocity is more important in kinetic energy .if the two cars, each with mass m travelling at 80 kph, collided head-on and remained in contact after the collision, both are stationary afterwards. If the crumple zone of each car is decreased by x = 0.5 m, a distance Δs that travelled by each car during the collision and if the magnitude of the average acceleration during the collision is A, the magnitude of the average force exerted by each car on the other during this collision is therefore mA. (Dolman, 1989) Therefore large crumple zone x gives a smaller force on the collision. If passengers’ are not wearing the seatbelt then, when the car starts decelerating during the collision, the passengers will travel with initial speed. In this case, the x for the passengers’ body may depend on how much the body deforms. In case of seatbelt, then the distance over which the body decelerates is more than the distance over which the car decelerates. Therefore, a larger value of x gives a smaller deceleration and therefore, a smaller force on the passenger’s body. The risk is further fuelled by reaction time – that is the, time it takes between an individual perceiving dangerous stimuli and reacting to it. Two cars of equal weight and braking ability are travelling along the same road. Car A, travelling at 70 kilometres/hour, is overtaking Car B, which is travelling at 50kilometres/hour. A wild animal – emerges from a driveway when the two cars are side-by-side. The drivers see animal at the same time take 1 second before they fully apply the brakes. In that one second therefore, care travel a large distance than car B .Car A is likely to hit the animal before Car B. In average,1.5 seconds is the reaction time of and therefore the driver who is driver who is distracted may take as long may take more time to react hence increasing the probability that an accident will occur.( Sera,2000) Braking distance -That is, the distance travelled by a car before stopping when the brakes are applied depends would depend on the slope or grade of the roadway is important .A vehicle will stop more quickly going uphill because gravity. Frictional resistance between the road and the cars tyres is also important – a car with new tyres on a dry road will not skid and will stop quickly than one with worn tyres on a wet road. If slope and frictional resistance are equal, then initial speed become the main factor influence on braking distance. Less control- because of high speeds making the cars become more difficult to control because if the net force acting on the car is zero then the car will continue to move in a straight line with no change in speed because of inertia. Inertia can be reduced by steering wheel to change the direction of the tyres in order to make the car deviate from the straight line in which it is travelling and go round the bend. The risk of being involved in a fatal crash increases with increasing speed especially at head on collision because the colliding speed is the sum of the speeds of the two vehicles involved in an accident which increases the impact hence great distortion of bodies involved. (Temple,1989) and (Michal,1976) References. Dolman, R, (1989).Statistical Mechanics. Oxford: Clarendon Press. New York Sera, (2000). Physics for Scientists and Engineers, 5th edition. Thomson Learning Inc. U.S.A. Toora, (2000).Technical Assessment of Seatbelt Usage and Effectiveness. Intech. Michal, W et al (1976). Individual Differences in Perceptual Information Processing and Their Relation to Automobile Accident Involvement: Journal of Applied Psychology, 61 (2):229-233. Temple, L,(1989).Perceptual and cognitive factors affecting driving ability of young and older drivers. Las Vegas: University of Nevada. Read More