Table of Content
- What do you think about weightlessness?
- What is weight?
- Weightlessness and why it happens?
- Weightlessness in physics
- The reason behind astronauts feel weightless
- Zero Gravity
Weightlessness is just a state of unopposed motion under gravity. All you need to do to create weightlessness is drop something. When you do that, you remove all of those opposing forces and the object falls. Weightlessness comes from this conflation of these two slightly different ideas. On the one hand, you have the weight you learn about in school, as a gravitational attraction. You have the slightly subtle idea of weight as something you experience and feel.
Before discussing weightlessness, we have to know, what is weight? Weight is nothing but the force due to gravity. Like all forces, it’s a vector, not a scalar. Mass is scalar because it doesn’t have a direction but the force is always a vector. So, it always has to point in a distinct way. When there is no opposing force, an object will fall and this, in fact, has a special state or name in physics. The object is in free fall as long as gravity is the only force move on it that means no opposing force from the ground, no air resistance so not falling at terminal velocity. Just need rest accelerating due to gravity without any other forces acting like this fellow as an example.
So, the body’s weight has not disappeared but it feels weightless because it can’t feel any force is pushing back on it to show that it has weight. So object orbiting the earth happen to be in freefall like the space shuttle in the image which as you can see always very fast.
They don’t fall back to what the earth because their weight force is always perpendicular to their motion. It’s moving so fast that by the time it starts falling towards the earth it’s actually moved across and so it curves around in a circle instead. So, all the time the space shuttle is falling towards the earth but it’s just moving so fast that it ends up going around the earth before it can land this means that the gravitational force acting like a centripetal force. It’s never acting in the identical direction as the spaceship is moving and never moving in the opposing direction.
It’s just a feeling experienced by a separate person when there are no visible objects moving one's body and applying a push or pull upon it. Weightlessness sense exist when all connecting forces are discarded. These senses are ordinary to any condition in which you are provisionally in a condition of free fall. When in free fall, the single force acting upon your body is the force of gravity which is a non-contact force. So, the force of gravity cannot be noticed without any other opposite forces, you have no feeling of it. You would notice weightless when in a state of free fall.
If you go any amusement parks for riders of roller coasters and different rides in which riders are provisionally airborne and scoop out of their seats. Assume that you were raised in the top of a very high tower and then your chair was instantly drop out. As you and your chair drop towards the ground, you both accelerate at the same rate - g. The chair is movable, falling at the same rate as you, it is incompetent to push upon you. Standard forces only result from contact with steady, assisting surfaces. Gravitational force is the single force acting upon your body. There are no outermost objects touching your body and applying a force. As such, you would practice a weightless sensation. You would consider as much as you always do yet you would not have any feeling of this weight.
Weightlessness is not only a feeling but also an unreal fit to separate who has lost weight. As you are free falling on a roller coaster ride in an amusement park, you have not directly lost your weight. Weightlessness has very small to do with weight and mainly to do with the existence of contact forces. The force of gravitational attraction to the Earth is referring by weight, a free-falling person has not "lost his weight;" he is still meeting the Earth's gravitational attraction. Woefully, the uncertainty of a person's real weight with one's feeling of weight is the source of many misunderstanding.
I think physicists would normally say weightlessness is a consequence of freefall, but maybe with this view of weight, it would be better to say that freefall is a consequence of weightlessness. As soon as you stop exerting other forces on an object, it has no choice.
Suppose I was standing on a scale in an elevator that’s at the top of a skyscraper I would see on the scale that my weight is 135 pounds. Now suppose somebody cuts the elevator cable what I will see on the scale in my free fall down the elevator shaft.
Just take a moment and think, then look at what’s on the elevator floor is falling the scale is falling. I’m falling, everything is falling. So, to say it as simply as I can any time you were able to move freely in response to gravity. It means there is nothing to restrain you from accelerating or decelerating. You are weightless or experiencing microgravity.
In the early days of space exploration, NASA developed a technique to recreate zero gravity. The notorious vomit comet because the weightless effect of microgravity is nothing more than a continuous free fall. It’s possible to simulate it by flying an aircraft in a huge art or parabola which for short period of time allow those on board to float as though in space but stomach-churning ride could spell trouble for some people. “Have you pondered that what it would be like to be an astronaut floating around in the space station?” “why is the astronaut floating?” “why do astronauts feel weightless?”
“There is no gravity in space”. The thing is that the moon orbits the earth due to gravitational attraction. Actually the space station is only about 400 kilometers away. So if you are in Sydney, it’s a little bit far than the drive to Canberra. But does it make sense that the big gravitational force is on you. Actually it’s on the astronauts which is just a short distance away.
The truth is the force on the astronauts is almost as much as the force on you. Then why are they floating while you are stuck here?
The truth is “the astronauts aren’t floating, they are falling and not only that but also the space station is falling as well”. But the space station doesn’t come impacting into the earth, because the space station and astronauts inside have this huge sideways velocity of about 28,000 kilometers per hour. Similarly, they are falling towards the earth, they are going so fast that as they fall towards the Earth’s surface it curves away from them.
If the earth didn’t place a gravitational force on them, they would fly out into space. So, as a result of that gravitational pull that they can actually keep orbiting the earth.
There is some more assumption related to it astronauts in the space shuttle feel weightless because:
1. “The earth gravitational field is very weak in space”.
2. “The astronauts have less mass in space”.
3. “The astronauts are falling at the same rate as the shuttle”.
The astronauts don’t completely feel weightless, they just feel weightless. This sensation of weightlessness means that even though you still have weight you just don’t notice it because there is no opposing force. Come to the next, “there is no gravity in space”; Completely Wrong. There is a gravity in space it’s what cause the planets to stay in orbit. It will cause the space shuttle to stay in orbit around the earth. Earth’s gravitational field is very weak in space. Now while it weaker than on the surface it is not all that much weaker at the altitude of the space shuttle the gravity is about 8.7m/s2, which is pretty close to that what we have on the surface. Of course, if we are going to Jupiter or something then this would be closer to the correct answer. The astronauts have less mass in space doesn’t work conservation of mass zero. The astronauts are falling at the same rate of the shuttle. This is, in fact, the correct answer. If you are falling at the same rate as an object you are inside at that means there is no opposing force to let you feel your own weight, which means they have a sensation of weightlessness.
Zero Gravity, which is also called Zero-G is the state or condition of weightlessness. We can also state that in which condition the net or a plain effect of gravity which is a gravitational force is zero.
It is possible for a body to be completely weightless when it falls freely in a uniform gravitational field. This is because the weight is felt due to the contact force exerted by the surface on which the body is placed.this force is uniform and reverse to the gravitational pull. During free fall this contact force becomes zero. For Example, this weightlessness can be felt while going down in an elevator or a roller coaster.
Watch this Video for more reference