onClipEvent (load) {
    V0 = 14;  // -14;
    // R = (70-90)*Math.PI/180;
    R = -70*Math.PI/180;
    Vx = V0*Math.cos(R);  // sin(R);
    Vy = V0*Math.sin(R);  // cos(R);
}
onClipEvent (enterFrame) {
    Vy += 0.3;
    _x += Vx;
    _y += Vy;
    /*
    if (Vx/Vy>0) {
        this._rotation = Math.atan(Vx/Vy)*180/Math.PI;
    } else {
        this._rotation = -Math.atan(Vx/Vy)*180/Math.PI;
    }
    */
    this._rotation = Math.atan(Vy/Vx)*180/Math.PI;  // 一部修正
}