Weightlessness due to gravitational field

AI Thread Summary
Astronauts in a space capsule at 900 km experience weightlessness due to free fall, despite gravity being about 90% of sea level strength. They are in orbit because their high tangential velocity counteracts the pull of gravity, creating a balance between gravitational force and centrifugal force. This results in a continuous free-fall motion around the Earth without actually descending. The gravitational field is not zero at that altitude; rather, it is the combination of gravity and orbital speed that creates the sensation of weightlessness. Understanding this balance clarifies why astronauts feel weightless while still under the influence of Earth's gravity.
scientict
Messages
3
Reaction score
0
Astronauts in a space capsule orbiting the Earth at a height of 900km experience weightlessness: hence the gravitational field due to the Earth must be zero at that altitude'.

Can someone please help ?
What does it mean?
 
Physics news on Phys.org
Someone posted that gravity at the space station is about 90% as strong as it is at sea level. The astronauts are in free fall, but moving fast enough perpendicually to the force of gravity that the inwards acceleration from gravity results in their path being an orbit around the Earth at a near constant speed and distance.
 
i still don't get it.. please explain clearly
 
Read this: http://75.126.60.30/showpost.php?p=1466077&postcount=2
 
Last edited by a moderator:
They're still experiencing gravity in an inverse square relation to their distance from the Earth's center.
However, so is their space capsule...

They're both free-falling back to the Earth with a tangential velocity that prevents them from ever actually reaching the earth.
 
In a nutshell: Force of gravity = Centrifugal Force from spinning around the earth
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »

Thread 'Newton's first law?'

Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
View full post »
Thread 'Beam on an inclined plane'

Thread 'Beam on an inclined plane'

Hello! I have a question regarding a beam on an inclined plane. I was considering a beam resting on two supports attached to an inclined plane. I was almost sure that the lower support must be more loaded. My imagination about this problem is shown in the picture below. Here is how I wrote the condition of equilibrium forces: $$ \begin{cases} F_{g\parallel}=F_{t1}+F_{t2}, \\ F_{g\perp}=F_{r1}+F_{r2} \end{cases}. $$ On the other hand...
View full post »

Similar threads

Why are astronauts outside a spaceship not pulled by Earth's gravity?
Replies
31
Views
4K
B Gravitatonal field force arrow diagram for Sun and Earth
Replies
2
Views
1K
Free Fall and gravitational field strength
Replies
1
Views
2K
How does gravitational potential energy work?
Replies
27
Views
11K
Conservation of energy in Gravitation
Replies
4
Views
1K
Constant velocity in a central force field
Replies
18
Views
1K
Where between the Moon and the Earth is the gravitational potential=0 ?
Replies
21
Views
3K
Confusion spinning falling objects vs spinning objects
Replies
1
Views
4K
I The gravitational center of the Earth
Replies
3
Views
2K
Potential Energy for "stone + field" physical system
Replies
13
Views
7K

Hot Threads

Recent Insights

Back
Top