import numpy as np

def dist(angle,m_prop):
    # constants
    n=1000                  # number of time steps to simulate
    rho=1.225               # kg/m^3
    g=-9.8                  # m/s^2
    start=0.0               # seconds
    end=10                  # seconds
    initial_height=5

    #insert loop
    initial_v=1500 * (m_prop/65)**0.45
# object
    A=.8            # surface area m^2
    C=1.4           # drag coefficient
    mass=65         # mass of object in kg

# parameters of simulation
    radians=np.radians(angle)

#initalize state variables
    t=np.linspace(start,end,n+1)
    vx=np.zeros(n+1)
    vy=np.zeros(n+1)
    x=np.zeros(n+1)
    y=np.zeros(n+1)

    y[0]=initial_height
    vx[0]=initial_v*np.cos(radians)
    vy[0]=initial_v*np.sin(radians)

# begin simulation
    for j in range(1,n+1):
        if y[j-1]<=0:
            vx[j]=0
            vy[j]=0
            y[j]=0
            x[j]=x[j-1]
        else:
            # the following code is _corrected_ from the wrong math
            v = np.sqrt( vx[ j-1 ]**2 + vy[ j-1 ]**2 )
            ax = -( 0.5*rho*C*A/mass ) * v**2 * ( vx[ j-1 ] / v )
            ay = g - ( 0.5*rho*C*A/mass ) * v**2 * ( vy[ j-1 ] / v )
            dt=t[j]-t[j-1]
            vx[j]=vx[j-1]+ax*dt
            vy[j]=vy[j-1]+ay*dt
            x[j]=x[j-1]+vx[j]*dt
            y[j]=y[j-1]+vy[j]*dt
            if y[j]<=0:
                y[j]=0
                x[j]=x[j-1]
                vx[j]=0
                vy[j]=0
    return x[n]