1.What is responsible for the __ g, we experience on the surface of the Earth?
2.Why do astronauts feel weightless in space shuttles?
3. Where in the body do we sense rotation?
1. The force of gravity is responsible for the weight, denoted as "g," that we experience on the surface of the Earth. To understand this, we need to know about Newton's law of universal gravitation, which states that any two objects with mass will attract each other with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. In the case of the Earth and objects on its surface, the mass of Earth is much greater than that of any object on its surface. As a result, we are pulled towards the center of the Earth, creating a force that we perceive as weight.
2. Astronauts feel weightless in space shuttles because they are in a state of free falling around the Earth. When a space shuttle orbits the Earth, it is continuously falling towards the Earth due to gravity. However, it is also moving forward with sufficient velocity, which causes it to continuously miss the Earth and curve around it. This constant state of free falling, where the Earth's gravity is counteracted by the forward motion of the shuttle, creates the perception of weightlessness for the astronauts inside. They experience a feeling of floating because they are essentially falling at the same rate as their spacecraft.
3. The ability to sense rotation is mainly attributed to the vestibular system, which is located in the inner ear. Within the inner ear, there are small structures called the semicircular canals, which contain fluid that moves when the head rotates. This movement of fluid stimulates tiny hair-like cells, which send signals to the brain. These signals help the brain perceive the direction and speed of rotations, allowing us to sense and maintain our balance. Hence, it is the vestibular system in the inner ear that enables us to sense rotation.