There is an interesting phenomenon in the film. Astronauts lose their center of gravity and float in the air. Everything in the capsule is weightless. So why do people lose weight in space? What is the principle of weightlessness?
Why is space weightless
In space, all objects lose their center of gravity, including people floating in space, as we have seen in the film. So why does space lose weight? What's the principle? Simply put, when an object is on the earth, it will be gravitated by the earth, and one of the components of gravitation is called gravity.
So if a person stands on the ground, the reason why we can keep still under the action of gravity is that the ground will give us a support force, and the size of the support force is equal to the gravity we are subjected to, and the resultant force of the two is zero, so there is no acceleration. But if a ball is thrown into the air, because there is nothing to give it an upward support, only gravity is called complete weightlessness.
Why is space weightless?
Because there is no support which can counteract the gravity, if there is such support, it is a normal state, and there is no complete weightlessness. Moreover, if there is such a supporting force, but its size cannot completely offset the gravity, it is called incomplete weightlessness, so the judgment of weightlessness is the size of the supporting force.
So in space, why is it called complete weightlessness? First of all, we are still affected by gravity in space, but even if this person stands on the surface of the satellite, he is still weightless. According to the above, the weight loss is based on the support force.
I will simply explain the situation of synchronous satellite around the earth, because people need a centripetal force for circular motion. As long as the centripetal force meets a certain size, it can become a uniform circular motion.
So if the gravity just satisfies the condition of centripetal force, we can complete the uniform circular motion around the earth without supporting force. Because there's no support, it's weightless. The above is the answer to the principle of weightlessness in space. I hope it can help you.