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Thought Of The Day_7_Gravity and Astronauts..!!

Note by Rohit Gupta
2 years, 3 months ago

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No sir. Satellites revolve because there is no net torque acting on them therefore conserving their angular momentum. Once the rocket puts them into orbit it is done. Rajdeep Dhingra · 2 years, 3 months ago

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@Rajdeep Dhingra @Rajdeep Dhingra yes you are right in saying that the angular momentum is conserved but the question was a little different.. y the astronauts feel weightlessness??? Rohit Gupta · 2 years, 3 months ago

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@Rohit Gupta ohh.. Sir I have misunderstood the question. Anyways sir I have asked U a doubt in a question (Balancing the ball). Please could U take the pain in seeing it sir. Rajdeep Dhingra · 2 years, 3 months ago

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@Rajdeep Dhingra @Rajdeep Dhingra Replied !!! Rohit Gupta · 2 years, 3 months ago

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@Rohit Gupta Thank You very much sir ! Rajdeep Dhingra · 2 years, 3 months ago

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@Rajdeep Dhingra Now I am waiting for your response there..!! Rohit Gupta · 2 years, 3 months ago

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@Rohit Gupta sir,here is my answer-

Yes, there is gravity in the outer space.

Regarding the astronauts feeling weightless, anyone feels weightless till there is no reaction(to the action force) force provider, and in free space it is the case.There is no reaction provider against the force of gravity, hence they have an acceleration towards the force provider and don't feel their weight.(The parts of their rocket cannot be considered as normal reaction provider, as the whole system of rocket and it's parts, including the astronaut will be accelerating towards the planet)

Now, for the satellites, the case is very much similar to rotational motion(or even circular motion), they have a tangential velocity(perpendicular to gravitational force) and force of gravity as centripetal force, and since about the force provider(i.e. the planet) there is no torque(ignoring the force of gravity of other heavenly bodies, as they are much farther away) acting, the angular momentum of satellites about the planet remains conserved, and hence they keep on revolving around the planet at at a fixed rate(not exactly fixed, if we remove the ignored factors). Abhijeet Verma · 2 years ago

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Weightlessness is when, in frame of the person himself, the effective gravity appears to be zero..!!
case 1) there is no gravity at all
case 2) person is falling freely under gravity (As in the case of satellite and astronauts)!! The whole satellite is in free fall towards earth..!! Rohit Gupta · 2 years, 3 months ago

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Yes there is gravity.

With the gravitational pull they also experience a centrifugal force in opposite direction to gravitational force.

Also this pull is the one who provides centripetal alteration, which is necessary for revolving.

If I went wrong somewhere them plz correct me. Kushal Patankar · 2 years, 3 months ago

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@Kushal Patankar Centrifugal force is just an imaginary force in frame of astronauts, how will you explain the case in a stationary frame attached to earth Rohit Gupta · 2 years, 3 months ago

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No, there is no gravity in the artificial satellites. The gravity exists only on the surface of the Earth and not inside or outside the Earth.
The satellite revolves around the earth just because of the critical velocity. This can be calculated with the formula V = √((G×M)/R) ,Where G is the gravitational constant. M is the mass of the body being orbited (Earth). R is the distance from the center of the Earth to the object in orbit. Still require anything, please reply...ok Ubaidullah Khan · 2 years, 3 months ago

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@Ubaidullah Khan If there is no gravity of earth near the satellite then what changes the direction of the velocity of satellite?? Rohit Gupta · 2 years, 3 months ago

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Although the Earth's gravity has a lesser effect on an astronaut orbiting the Earth in a spaceship than on a person on the surface of the Earth, this is not the reason why an astronaut experiences weightlessness.

The space shuttle, International Space Station and most other manned vehicles don't get that far from the Earth. The Earth's gravitational attraction at those altitudes is only about 11% less than it is at the Earth's surface.

If you had a ladder that could reach as high as the shuttle's orbit, your weight would be 11% less at the top. Put another way, a person who weighs 100 kg on the Earth's surface would weigh about 89 kg at the top of the ladder.

The reason why the person wouldn't feel weightless is because they are being pushed by the ladder - it is keeping them from falling.

If they were to jump off the ladder, then they would feel weightless, at least up until the time they splatted on the ground.

This is why astronauts feel weightless. The astronaut, the spaceship and everything inside it are falling towards the Earth.

The reason why the astronaut doesn't go splat is because the Earth is curved and the astronaut, the spaceship and everything inside it are moving 'sideways' fast enough that, as they fall towards the Earth, the surface of the Earth curves away from them.

They are always falling towards the Earth, but they never get there. . . . . .

Source

And sir, try solving Cool space question and Gravity weightlessness for interesting questions. . . . . \(\huge\ddot\smile\) Sravanth Chebrolu · 2 years, 3 months ago

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@Sravanth Chebrolu This answer is given by Steve Gagnon, Science Education Specialist . You can see the answer by clicking here. Nihar Mahajan · 2 years, 3 months ago

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@Nihar Mahajan Thanks! I've added the source. Sravanth Chebrolu · 2 years, 3 months ago

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@Sravanth Chebrolu It seems that Sravanth has just copied all the answer and gave himself the credit Rajdeep Dhingra · 2 years, 3 months ago

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@Rajdeep Dhingra @Sravanth Chebrolu I didn't expect you to do this again. Nihar Mahajan · 2 years, 3 months ago

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@Nihar Mahajan I'm sorry, I forgot that here, but you can see in the cool space question that I had mentioned the source, sorry again for my mistake. Sravanth Chebrolu · 2 years, 3 months ago

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@Rajdeep Dhingra Thanks! I've edited that. . . Sravanth Chebrolu · 2 years, 3 months ago

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@Sravanth Chebrolu Bravo..!! That is the correct reasoning..!! Rohit Gupta · 2 years, 3 months ago

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@Rohit Gupta Yes sir, but that was not by me please see the source. Also I sorry for marking the wrong option in my question, the correct answer must be "The normal force is Zero", or atleast, that's the correct answer given in NSO paper, what's your say sir? Sravanth Chebrolu · 2 years, 3 months ago

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@Sravanth Chebrolu yeah in that scenario normal reaction by chair has to be zero..!! Rohit Gupta · 2 years, 3 months ago

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@Rohit Gupta Anyways, I've deleted that sir. . . Sravanth Chebrolu · 2 years, 3 months ago

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@Sravanth Chebrolu Ok!! Rohit Gupta · 2 years, 3 months ago

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