Explanation of tying hemp ropes before and after to increase friction in chapter 12
The soldier was surprised that readers kept raising objections to this question. At first he thought it was just a few people, but he didn't expect that people would keep raising it for so many days...
My son is now in his first year of high school. When he was out of school just now, I asked him to draw a diagram and do a stress analysis on this issue. He drew it in less than a minute and said that this is knowledge for junior high school.
This is indeed junior high school physics knowledge...
Simply put, when a carriage goes uphill, it is subject to the downward gravity component along the slope and the upward pulling force along the slope. If the gravity component is greater than the pulling force, that is, when the carriage is going to fall down, the friction force is in the same direction as the pulling force.
To put it more vividly, by increasing the friction, you can stop and take a rest when you can't drag it. Relying on friction, only a small amount of pulling force can keep the carriage from sliding down... If the friction is too small, the road surface will
If it's too slippery, you won't be able to stop in the middle and have to pull up the steep slope until you reach level ground.
This is also the reason why the tires of hand trucks and trolleys need to be patterned to increase friction.
Another note: This book will involve a lot of physics knowledge in the future. Soldiers should try their best to explain it clearly so as not to misunderstand it.