변위,displacement - VeryGoodWiki

다른 두 위치,position의 차이,difference. 그 크기(길이)는 최단거리(직선거리).
Change of position.

기호: Δx, $\Delta\vec{r}$ 등

$\Delta x=x-x_0$
$\Delta x=x_f-x_i$
$\Delta\vec{r}(t)=\vec{r_f}-\vec{r_i}$

단위: 길이,length와 같다. SI단위 m (meter).

입자가 움직여서 그 위치벡터,position_vector가 $\vec{r_1}$ 에서 $\vec{r_2}$ 로 바뀌면, 입자의 변위 $\Delta\vec{r}$ 은

$\Delta\vec{r} = \vec{r_2}-\vec{r_1}$

다음과 같이 쓸 수도 있음

$\Delta\vec{r} = (x_2-x_1)\hat{\rm i}+(y_2-y_1)\hat{\rm j}+(z_2-z_1)\hat{\rm k}$
$=\Delta x \hat{\rm i}+\Delta y \hat{\rm j}+\Delta z\hat{\rm k}$

The displacement vector from the point $\rm P$ with the coordinate $x$ to $\rm Q$ with $x'$ is defined by

$\Delta\vec{x} = \vec{x}'-\vec{x} = (x'-x)\hat{e_1}.$

A 위치벡터,position_vector $\vec{x}$ is the displacement from the 원점,origin to a point representing the Cartesian coordinate $x.$

//MKL homogeneity (OF SPACE)

homogeneity
We assume that a straight line(직선 ... 직선,line) is a one-dimensional Euclidean space. The displacement of $L\hat{e_1}$ is identical to any displacement from $x\hat{e_1}$ to $(x + L)\hat{e_1}$ for all allowed $x.$ This is called the homogeneity of space.

MKL isotropy of space // 등방성,isotropy
We also assume that a straight line in any direction has the same property that the magnitude of the displacement of $L\hat{e_1}$ is identical to any displacement from $x\hat{n}$ to $(x + L)\hat{n}$ for all allowed $x$ and for any unit vector along any direction. This is called the isotropy of space.

In mathematics, homogeneity and isotropy of space are axioms that are assumed to be true and one does not attempt to prove them.
In physics, these are called postulates that have never been disproved by countless experiments.
However, a postulate is only one of the beliefs that could break. For example, some of the postulates of Newtonian mechanics are now discarded with the advent of relativity.

(X2K 13m)

Compare: 변위는 벡터, 이동거리,distance는 스칼라.

변위의 정도는 최단거리(직선거리). 이동거리는 그 이상. 항상 다음 부등식,inequality이 성립.

이동거리 ≥ 변위

(See also 스칼라와_벡터_비교)
변위:속도,velocity = 거리,distance:속력,speed
｜변위｜ = 거리 CHK

어원은 아마도 위치(place)를 바꾼다(dis-)???? CHK

시간에 따라서 계속 미분하면,

변위,displacement

↓

속도,velocity

↓

가속도,acceleration