...s and velocity: An external force acting on a body causes the body to accelerate. The force is equal to the rate of change of momentum of the body. This is, in fact, Newton’s Second Law of Motion: If the mass of the body remains c***tant, then and, 运动学(kinematics)和动力学:...
...之前,让我们先定义位移,然后学习什么是位置向量以及如何编写它。 位移的定义 位移是对粒子初始位置和最终位置之间差异的测量。它是运动学中使用的基本量之一,也用于导出速度和加速度。位移是一个向量量,它有一个...
...hen, we can write, . Since , Since we found when we looked at finding angular speed, we can also write this acceleration as We can also show that the direction of this acceleration, which is in the direction of , is directed towards the centre of the circle. C***equently, this acceleration is...
...ircle at a c***tant speed sweeps through an angle of in a time of , the angular speed of the object is defined as, 角速度的单位是弧度每秒(rads-1) The time taken by an object moving in a circular path to move through one full cycle is called the period, . In other words, the obj...
...能使汽车完全停车。 For the car, we have , , , . To find the acceleration, we use (which is an altered form of the more familiar ). Then, . The size of average friction is then, . 由于摩擦力作用于160 m的距离,所做的功为: . 例3 地球和太阳之间的引力...
...使用“suvat”运动方程。 If the kinetic energy of the body after acceleration is , we can find it by where is the size of the c***tant force, is the mass of the object, isthe c***tant acceleration and is the displacement. From the equation , we have . Since our initial velo...
...单位是kg m s-1。本文详细讨论了线动量。 什么是角动量(angular momentum)? For an object with mass moving at a velocity , the angular momentum with respect to a reference point is defined using the cross product as: where is the position vector of the object that descri...
...计算恒定加速度下的平均速度: 计算加速度 Instantaneous acceleration is the change in velocity divided by the duration of the interval dt: i.e. the derivative of the velocity vector as a function of time. Average acceleration over a period of time is the change in velocity ()...
angular 4的一个主要优点是,与angular 2相比,它将捆绑文件大小减少了60%。它还向后兼容angular 2,并兼容较新版本的typescript,如typescript 2.1和typescript 2.2。这样做的好处是它改进了类型检查,...
关键区别:速度是指距离相对于时间的变化率。它是一个矢量,也就是说它既有方向又有大小。角速度计算旋转物体的角位置相对于时间的变化率。 速度是指距离相对于时间的变化率。它是一个矢量,也就是说它既有方向又有...