1, the weight of the kite string itself and the role of the earth's gravity.
2. The influence of the wind.
The kite line is not straight in the air, but hangs in the middle. Why is this happening? Because both ends of the rope not only have the power of kite rising and hand pulling down, but also the weight of the rope itself, the middle of the rope is bent downward into an arc. The longer the rope hanging in the air, the greater its own weight and the gravity of the earth, and the greater the radian of hanging. When the kite is not high, the arc of the rope hanging down is very small and it is not easy to see.