A.Use newtons first law to explain why whiplash occurs?
B.why are cars fitted with head rests?
A. Newton's first law of motion, also known as the law of inertia, can help explain why whiplash occurs. According to this law, an object at rest will remain at rest, and an object in motion will continue in motion at a constant velocity unless acted upon by an external force.
In the case of whiplash, consider a car accident where your vehicle is struck from behind. Initially, your body is moving forward with the car at the same velocity. However, when the car gets hit, an external force suddenly decelerates the car. According to Newton's first law, your body will continue moving forward at the original velocity due to inertia.
However, the head, being the heaviest part of the body and not firmly restrained by the seat, tends to lag behind the forward motion. As a result, your head moves backward suddenly, stretching the muscles and tendons in your neck. Then, as the head reaches its furthest point of backward movement, it abruptly moves forward again, causing the muscles and tendons to overstretch in the opposite direction. This rapid back-and-forth movement of the head creates a whip-like motion, hence the term "whiplash."
B. Cars are fitted with headrests primarily for safety reasons. Headrests provide several benefits, including:
1. Reducing the risk of whiplash: As mentioned above, whiplash occurs when the head rapidly moves backward and then forward. By having a headrest, it provides support for the head and limits its movement during a rear-end collision, thus reducing the risk of whiplash injuries.
2. Preventing spinal injuries: In addition to whiplash, headrests also help protect the spine. They are designed to align with the natural curvature of the neck and upper back, providing support and preventing excessive flexion or extension of the neck during an impact.
3. Minimizing the risk of head injuries: Headrests act as a cushion between the head and the car seat, reducing the likelihood of severe head injuries in case of sudden stops or accidents.
It's important to note that headrests should be adjusted properly to be effective. They should align with the center of the head, slightly above the ears, to provide optimal support and protection in case of an accident.