![]() And what's that funny smell? Here is a diagram for the upward accelerating elevator (and you). If your elevator is like the one in this building, you might feel frustrated at how slow the damn thing goes. ![]() During the short interval that the elevator accelerates upwards, how do you feel? Anxious? Or maybe you feel a tad bit heavier. The magnitudes of these two forces have to be equal in order for the net force to be zero.Įxample 2: Now push the "up" button. The two forces on you are the force from the floor pushing up and gravitational interaction with the Earth pulling down. If your acceleration is zero, the net force must also be zero (technically, the zero vector). Since you are at rest and staying at rest, you are in equilibrium (acceleration is zero). How do you feel? Awkward? Here is a diagram. Just stand there so that the elevator is at rest. Suppose I start with some examples.Įxample 1: Go stand in an elevator. What is your apparent weight? Let me go ahead and say that what you are feeling right now isn't really gravity. Maybe I should talk about how you feel weight. There is an interaction even though there is no air between them. Here is John Young's "jump salute".Īnd what about the Earth itself? Why does it orbit the Sun? It orbits because there is a gravitational force between the two objects. There is no air on the moon, but astronauts don't float away - even when they jump. ( link here) This is a picture of the mass before the air was pumped out.Īnother example is the moon. I made a video of a mass hanging from a suction dart inside a vacuum bell. Basically, it is a demonstration of how a suction cup works. You can probably find some examples of why this isn't the cause of "weightlessness". So, this isn't the correct explanation for "weightlessness". The gravitational force in orbit is 89% as large as on the surface. What would be the weight (gravitational force) on the astronaut both on the surface and in orbit? The only difference will be the distance between the astronaut and the center of the Earth. A typical height for an orbiting Space Shuttle is about 360 km above the surface of the Earth. Doesn't this expression say that the gravitational force gets weaker as you get farther from the Earth? Yes. I used rounded values in the calculation so that it is off just a bit.
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