中国大学 MOOC 课程 《Python 语言程序设计》第七周课上练习

中国大学 MOOC 课程 《Python 语言程序设计》第七周课上练习

1、铅球运行轨迹

from math import pi,sin,cos,radians
def main():
    angle,vel,h0,time = getInputs()
    xpos,ypos=0,h0
    xvel,yvel=getXYComponents(vel,angle)
    while ypos>= 0:
        xpos,ypos,yvel=updatePosition(time,xpos,ypos,xvel,yvel)
    print("\nDistance traveled:{0:0.1f}meters".format(xpos))

def getInputs():
    angle = eval(input("Enter the launch angle (in degrees):"))
    vel = eval(input("Enter the initial velocity (in meters/sec):"))
    h0 = eval(input("Enter the initial height (in meters):"))
    time = eval(input("Enter the time interval: "))
    return angle,vel,h0,time

def getXYComponents(vel,angle):
    thera=radians(angle)
    xvel=vel*cos(thera)
    yvel=vel*sin(thera)
    return xvel,yvel

def updatePosition(time,xpos,ypos,xvel,yvel):
    xpos=xpos+time*xvel
    yvell=yvel-9.8*time
    ypos=ypos+(yvel+yvell)/2.0
    yvel=yvell
    return xpos,ypos,yvel
main()