Adili is famous for walking on a tightrope across the Three Gorges of the Yangtze River, and is hailed as China's "Prince of High Altitude". When he walks on the tightrope, he always holds a 10-meter-long balancing pole in his hand. What is the function of this balancing pole? Let's start with how people stand and walk. From a mechanical perspective, any object must maintain balance when its gravity line (the vertical line passing through the center of gravity) must pass through the supporting surface (the contact surface between the object and the supporting object). If the gravity line does not pass through the supporting surface, the object will fall over. When a person stands upright on the ground without falling over (that is, maintaining stable balance), the condition is that the gravity line passing through the center of gravity of the person must be within the supporting surface formed by the outer edges of the two feet. When a person walks, he leans forward with one foot in front, and the gravity line drawn from the center of gravity of the person goes beyond the bottom surface of the foot, so the person leans forward. But before this fall can happen, the foot in the air quickly lands on the ground in front of the gravity line drawn from the center of gravity, so the lost balance is restored.
Similarly, a person walking on a tightrope must always make sure that the gravity line of his body passes through the supporting surface, which is the tightrope. The tightrope is very thin, and the contact surface with the human body is too small. When walking on the tightrope, as the person's posture changes, the center of gravity of the person will change, and the gravity line may deviate from the contact surface between the foot and the tightrope at any time, making the person lose balance and fall off the tightrope. If the person holds a balancing pole, the situation will change greatly. Because a well-trained person has enough time to adjust the balancing pole in his hand to adjust the position of his center of gravity, so that the gravity line passing through the center of gravity of the person will not go beyond the contact surface between the foot and the tightrope. Therefore, when walking on a tightrope, holding a long pole in his hand, when the center of gravity deviates, he can adjust the length of the pole on both sides of his body to restore balance, and this pole actually plays the role of "extending his arm". Especially when the wind blows from the side, the wind direction and wind force are constantly changing, and it's easy for the tightrope walker to lose balance. At this time, it's even more necessary to use a long pole to adjust the center of gravity and maintain balance. Therefore, when walking on a tightrope, holding a long pole or an umbrella with a handle can help the body maintain balance.