# Displacement (位移) Jamie Chen
Get Started. It's Free Displacement (位移) ## 2. Velocity (速度)

### 2.2. Average Velocity (平均速度)

2.2.1. The ratio between the total displacement and the total time taken by the body during motion is called average velocity. (人体在运动过程中所消耗的总位移与总时间之比称为平均速度)

2.2.2. Average velocity doesn’t give the detailed description of motion between two points. The path may be straight or curved and the motion may be steady or variable. The detailed analysis of motion is described by the instantaneous velocity. (平均速度并未详细说明两点之间的运动。 该路径可以是直的或弯曲的，并且运动可以是稳定的或可变的。 运动的详细分析由瞬时速度描述)

### 2.3. Instantaneous Velocity (瞬时速度)

2.3.1. The velocity of the object at any instant of time is called instantaneous velocity. or The limiting value of average velocity as the time interval approaches to zero is called instantaneous velocity. (物体在任何时刻的速度称为瞬时速度。 或随着时间间隔接近零，平均速度的极限值称为瞬时速度)

### 2.4. Uniform Velocity (匀速)

2.4.1. A body is said to have a uniform velocity if it covers equal displacement in equal intervals of time. (如果物体在相等的时间间隔内覆盖相等的位移，则该物体具有均匀的速度)

### 2.5. Variable Velocity (可变速度)

2.5.1. A body is said to have a variable velocity if it covers unequal displacements in equal intervals of time. (如果一个物体在相等的时间间隔内覆盖了不相等的位移，则称其速度可变)

## 3. Acceleration (加速度)

### 3.1. The time rate of change of velocity of the body is called acceleration. (人体速度的时间变化率称为加速度)

3.1.1. As velocity is a vector so any change in velocity may be due to change in its magnitude or a change in its direction or both. (由于速度是矢量，因此速度的任何变化都可能是由于其大小的变化或方向的变化或两者兼而有之)

### 3.2. Average Acceleration (平均加速度)

3.2.1. The ratio between the total change in velocity and the total time taken by the body during motion is called average acceleration. (速度的总变化与人体在运动过程中所花费的总时间之比称为平均加速度)

### 3.3. Instantaneous Acceleration (瞬时加速度)

3.3.1. The acceleration of the object at any instant of time is called instantaneous acceleration. Or The limiting value of average acceleration as the time interval approaches to zero is called instantaneous acceleration. (对象在任何时刻的加速度称为瞬时加速度。 或随着时间间隔接近零，平均加速度的极限值称为瞬时加速度)

### 3.4. Positive Acceleration (正加速度)

3.4.1. A body is said to have positive acceleration if its velocity increases. (如果物体的速度增加，则称其具有正加速度)

### 3.5. Negative Acceleration (负加速度)

3.5.1. A body is said to have negative acceleration if its velocity decreases. (如果物体的速度降低，则称该物体具有负加速度)

### 3.6. Uniform Acceleration (均匀加速)

3.6.1. If the velocity of the body changes by equal amount in equal intervals of time, then the body is said to have uniform acceleration (如果身体的速度在相等的时间间隔内变化相等的量，则称该身体具有均匀的加速度)

## 4. Velocity-Time Graph (速度时间图)

### 4.4. Applications of Velocity Time Graph (应用)

4.4.1. The average acceleration of object can be determined from the slope of velocity-time graph. (物体的平均加速度可以从速度-时间图的斜率确定)

4.4.2. The area between the velocity time graph and time axis is numerically equal to the distance covered by the object. (速度时间图和时间轴之间的面积在数值上等于对象所覆盖的距离)