模拟抛体的运动。允许用户自己输入抛体的初速度及倾角。模拟时，先显示出坐标轴及最高、最远点坐标（白色），然后进行动态模拟（红色），并显示任意时刻读速度方向（切线）。-Simulated projectile movement. Allow the user to enter the projectile initial velocity and angle. Simulation, the first axis and shows the highest, the farthest point of coordinates (white), then the dynamic simulation (red), and displays the read speed at any one time direction (tangent).