The Physics Behind Car Safety Features

THE PHYSICS BEHIND CAR SAFETY FEATURES

Cars contain several different types of safety features. These numerous safety features all have their own significance to the driver, as well as to the passengers. The purpose of this report is to show and express how physics is involved in automobile collisions and similarly how it is used to prevent injuries during accidents. Isaac Newton’s three laws of motion are used to describe the purpose of the three main safety features that cars are obliged to consist of; seatbelts, airbags, headrests, those of which all will be discussed in depth later below.

The absolute purpose of the seatbelt is to firmly hold the passenger in a way that the individual is almost a fragment of the car. This in return prevents the passenger from flying forward when the vehicle comes to a halt suddenly in case of a collision or rapid deceleration. This situation can be better explained with Isaac Newton’s 1st law of motion regarding inertia; an object in motion continues in motion with the same speed and direction unless acted upon by an unbalanced force. Suppose the car is the object in motion. As the car collides with another object or if the car comes to an abrupt stop, the brakes or the collided object provide an opposite force which changes the speed and direction of the prior moving car. Simultaneously, when all this is happening, the force to slow down isn’t applied on the passenger causing the individual to continue to travel in the same direction and speed as the car was travelling, causing severe, fatal injuries and even death. The seatbelt catches the passenger and becomes the protagonist at this instant. Seatbelts stop inertia from your body to keep travelling in motion when the car comes to a sudden stop; it forces your body to stop with the car.

Airbags are the leading safety feature in today’s cars and are of which are implanted in the dashboard, steering wheel and occasionally the sides of cars. Airbags are required to inflate and help the driver and passenger in the car to reduce their speed in severe automobile collisions without injuring themselves. This progress can be explained using Isaac Newton’s 2nd law of motion; the acceleration of an object is directly proportional to the unbalanced force acting on it and inversely proportional to its mass, which is expressed as the equation f = ma, where f stands for force, m stands for mass and a stands for acceleration. Force, mass and acceleration are all closely linked to each other and differ if one of their values are altered, for instance acceleration decreases as mass increases as more force is needed to move the heavy object. Back to discussing about airbags relating to the second law, all objects in a moving car have mass, direction and speed and so if the object is not secured properly in the car they will continue travelling in the same direction with the same speed when the car decelerates abruptly or in case of a collision until a force acts upon them. Every moving object has momentum, this being the product of the individuals mass and velocity. In order for the individual’s momentum to stop, there must be an acted force. An airbag provides this force over the time of a collision. This force provided by the airbag is known as impulse. Impulse is the product of the force applied to an object and the time taken of the force applied. The more time the force has to act on the passenger to slow them down, the lesser amount of damage is impacted to the passenger.

In summary, momentum is the product of mass and velocity, impulse is the product of force and time and it is also known that momentum is equal to impulse thus why mass x velocity = force x time. As of this and regarding airbags; f=mv/t, the airbag increases time since velocity and mass cannot be controlled. As a result of this the airbag increases the time of impulse therefore decreasing the force applied on the head and face of the driver and passenger as force, mass, velocity and time are in relation to each other.

Crumple zones are another example of a safety feature in a car which are in relation to Newton’s 2nd law. Crumple zones are located in the front and back part of the car and are made up of malleable metal designed to easily deform and crumple when the car collides with something. These crumple zones absorb majority of the energy of the impact which in turn prevents the impact from being transmitted to the individual in the car. Moreover, crumple zones increase the time of collision as of the metal taking time to crumple and thus why the force is decreased.

In every car headrests are to prevent neck and spinal cord injuries that occur over the time in vehicle collisions. The manner on how the neck is injured can be used to explain with the help of Isaac Newton’s 3rd law of motion; for every action, there is an equal and opposite reaction. When a car that is travelling comes to an abrupt stop or in case of a collision the body of the passenger or driver stays in the same position as of the seatbelts yet the head of the driver is thrown either forwards or backwards. As soon as the head is thrown either way it is naturally thrown back the other way as reasoning with Newton’s 3rd law.

In conclusion physics play a huge role in cars and their safety features. Seatbelts implement on Newton’s 1st law regarding inertia of how they stop and catch one’s body if the car suddenly comes to a halt. Airbags and crumple zones both help reduce the impact during collisions and describe Newton’s 2nd law concerning how force, acceleration and time all link to each other. Headrests are designed to help prevent neck injuries with the help of Newton’s 3rd law of motion. Car safety should always be put into consideration and never ignored as it is never certain where or when an accident may take place. Safety comes first.

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