When car crashes occur, the car’s contents and the passengers ones decelerate rapidly. Due to this, there’s a change in momentum because of the great forces, which can cause injury. A change in momentum happens when a force is given to an object that can move or that is currently moving. Moreover, modern cars have many safety features that absorb kinetic energy when a collision occurs and that reduce the chance of injury if a crash happens.
And these are:
Seat belts. They are extremely important and their job is to hold the passenger in place, which prevents from flying forwards as the car stops unexpectedly in the case of a collision. When the car stops, due to a collision with another object, the car’s acceleration decreases rapidly in a short period of time. This is also known as deceleration. They attach your body mass to that of a car, which means that you decelerate or accelerate when a car does the same. When the person continues in their same direction and speed, ( same speed and direction that the car was going ) the seat belt comes into play. Indeed, it catches them, holding them back from flying in the air. Seat belts are specifically designed to stretch a bit during a collision, which increases the time taken for the body’s momentum to reach zero, reducing the forces on it. If a car were to have an accident after travelling at a constant velocity, and the passenger was not wearing a seatbelt, a force would have to act on the person in order to slow them down. This force could come from the windshield or dashboard as the person crashes into it, causing serious damage.
Finally, one part of the seatbelt rests over the passenger’s pelvis while the other one rests over the shoulder and across the chest.
Headrests. They are found in every car and they prevent neck injuries. It is all thanks to physics that we understand how the neck becomes injured.
They are really efficient because they can be adjusted to fit the driver or passenger. If it is in any case not properly adjusted, it could cause injuries.
When there is a collision the body remains in the same position but the head is thrown backwards or forwards.
When it is thrown one way, it naturally goes the other way as well due to the neck muscles and vertebrae forcing it that way. When it is thrown at the other way it goes faster than when it was thrown in the first direction. This all because of Newton’s Laws.
Imagine: What happens when a person is standing still and getting pushed by another person? Well, when the person goes towards the other person, they are going at a certain speed while the standing person is not moving. As they push the person, they seem to remain in almost the same position, maybe taking a step or two forwards and their head moving forwards and backwards.
It is the same with a car. Picture it going at a certain speed and it hits a car with a person in it. The person in the car that was hit could have neck injuries due to the impact if their headrests were not adjusted correctly. Keep in mind that also the person in the first car might have neck injuries because they are travelling at a certain speed and then suddenly stopping due to the collision.