Discussion
All roads lead to Rome is a common idiom used to mean that the same goal can be arrived at using different routes. But the history of this saying has a lot of significance to physics in terms of vectors, scalars, displacement and distance. Rome was the heart of activity during the times of the Roman Empire. Every road in the empire would either directly lead to Rome or link to a major road leading to Rome. Putting this into the physics perspective, vectors, scalars, displacements and distance are measurements that have a starting point and an endpoint.
A vector has both direction and magnitude. Movement in a specified direction constitutes displacement while distance is the measurement from one point to another. Therefore, Rome was like a common point where all roads converged. For example, each road can be considered to be a vector that converges to a point which is Rome. The displacement resulting from this vector constitutes the distance between the starting point of the road and Rome.
Headrests in a car are used for safety purposes for passengers. In a car, passengers’ motion is governed by the Newton’s Laws specifically Newton’s First Law. Also called the Law of Inertia, it states that an object remains at rest or in motion in the same direction and with the same speed unless an unbalanced force acts on it. Therefore in a car, a headrest is used to protect the neck of the occupier from getting injured if the head is thrown backwards the moment when the car is bumped from the rear. This is because the person experiences an unbalanced force from behind that causes the head to have a backward movement.
