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Safety is a way of life. Safety Features that should be present in every car . Features. Safety Belts Air Bags Crumple Zone. Safety Belts. Designed to secure the occupant of a vehicle against harmful movement that may result from a collision or a sudden stop .
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Safety is a way of life Safety Features that should be present in every car
Features • Safety Belts • Air Bags • Crumple Zone
Safety Belts • Designed to secure the occupant of a vehicle against harmful movement that may result from a collision or a sudden stop. • Intended to reduce injuries
The science behind it? • How does it do so? • By increasing the time of impact, seat belts will result in lesser impact force. • The stopping force of seat belts prevents wearers from hitting other passengers or hard materials inside your vehicle. What if you’re not wearing a seat belt at all? • Its stops the wearer from hitting hard interior elements of the vehicle, or other passengers (second impact), • Makes sure that wearer is in the correct position for the airbag to deploy • Prevent the passenger from being thrown from the vehicle.
Based on Newton’s 2nd Law • The product of average force and the time it is exerted is called the impulse of force. • The impulse of force can be extracted and found to be equal to the change in momentum of an object provided the mass is constant:
Therefore, • If an impact stops a moving object, then the change in momentum is a fixed quantity, and extending the time of the collision will decrease the impact force by the same factor.
Other applications • This similar concept is applied to car baby seats which are specially designed for toddlers and children who cannot fit in to a normal seat belt. • They have the same aim as the seat belt in reducing injuries.
Air Bags • While the driver will still experience the same average impact force while wearing a good seatbelt, the airbag helps by exerting an equal pressure on all points in contact with it. • The same force is distributed over a larger area, reducing the maximum pressure on the body.
The science behind it? • Thus, the air bag helps to cushion the impact of the driver in a collision.
Therefore • Similar to the safety belt, the amount of damage done to a person depends on the change in momentum. • Airbags reduce the amount of damage dealt to a person by extending the period of time they are subject to a force.
Going further • When encountering a car collision, the driver and passenger tend to keep moving in accord with Newton's first law. Their motion carries them towards a windshield that results in a large force exerted over a short time in order to stop their momentum. If instead of hitting the windshield, the driver and passenger hit an air bag, then the time duration of the impact is increased.
Going further • Also, dashboards are padded. If air bags are not deployed, then the driver and passengers might collide with the windshield or. If the driver or passenger should hit the dashboard, then the force and time required to stop their momentum is exerted by the dashboard. Padded dashboards serve to extend the time duration of the impact, thus minimizing the effect of the force.
Crumple Zone • To protect car occupants, crumple zones manage crash energy, absorbing it within the outer parts of the vehicle, rather than being directly transmitted to the occupants. • This makes the passengers encased in a safety cell during collisions
The science behind it • Newton's second law states that force is proportional to acceleration. • Crumple zones deform relatively slowly when hit by another car or object, and thus delay the impact on the passengers. The additional time reduces deceleration and therefore, force on the occupants.
Resources • http://www.autotravel.gr/uploads/Image/drive%20smart/safety_belt.jpg • http://www.yourwaycarrental.co.nz/images/range/Child-and-Baby-Seat.jpg • http://uhaweb.hartford.edu/kgreenber/airbags.jpg • http://www.2carpros.com/images/articles/safety/seat_belt/drivers/safety_belt.jpg • http://en.wikipedia.org/wiki/Seat_belt • http://hyperphysics.phy-astr.gsu.edu/hbase/impulse.html#c2 • http://www.blogcdn.com/www.autoblog.com/media/2008/11/3-carbon-fiber-babyseat_opt.jpg • http://upload.wikimedia.org/wikipedia/en/thumb/e/e7/Peugeot_306_airbags_deployed.jpg/300px-Peugeot_306_airbags_deployed.jpg • http://wiki.answers.com/Q/Physics_behind_how_an_airbag_reduces_injury • http://www.physicsclassroom.com/class/momentum/u4l1c.cfm • http://500sec.com/wp-content/uploads/2010/03/mercedes-w116-s-class-12.jpg • http://en.wikipedia.org/wiki/Crumple_zone