How big do you have to be to have gravity?
Physicist: The answer to the first question is a bit smart-assed. The object needs to be bigger than you, or (most people would say) you’d be attracting it. No matter how small an object is, if it has mass, it has gravity.
Is there gravity inside a hollow planet?
The gravitational force you would feel inside the hollow planet is zero.
Why the gravitational field inside the hollow sphere is zero?
According to the shell theorem, spherically symmetric bodies will produce a gravitational field that affects all the external objects outside it as the mass is concentrated in a particular point in the spherically symmetric body. Therefore the gravitational field inside a hollow spherical will be zero.
Can spherical objects be treated as point masses?
Two big objects can be considered as point-like masses, if the distance between them is very large compared to their sizes or if they are spherically symmetric. For these cases the mass of each object can be represented as a point mass located at its center-of-mass.
Is gravity the weakest force?
Though gravity holds planets, stars, solar systems and even galaxies together, it turns out to be the weakest of the fundamental forces, especially at the molecular and atomic scales.
Is it possible for something to orbit a human?
It depends on your mass and the mass and distance of nearby objects. So you can have two astronauts orbit each other out in intergalactic space. But in earth orbit, that would not be possible. The gravity of the earth perturbs things too much.
How would gravity work if the earth was hollow?
No core means no magnetic field, and no magnetic field means that the Earth would be pretty dead. A hollow Earth would be less than 0.4\% of its current mass. The gravity on a hollow Earth would be so weak, it wouldn’t be enough for you to stick to the planet. You’d fly away into space.
What would gravity be like in a hollow Earth?
Gravity at center of the earth is zero, inside the hollow sphere.
What is gravitational potential inside a hollow sphere?
Gravitational potential is defined as the work (energy) required to move the object to an infinite distance free from gravity. The work required to move the object from the center of the sphere, if it is uniform, to the surface of the sphere, is zero. So the potential is the same everywhere inside the sphere.
What is the gravitational force on a body inside a hollow spherical shell?
The net gravitational force on a point mass inside a spherical shell of mass is identically zero! This proves that the force from any spherically symmetric mass distribution on a mass inside its radius is zero.
Can you discuss whether spherical objects for example planets can be treated as point masses?
Only objects with a spherical mass distribution can be considered as point masses. The Earth is not spherical.
What would be the magnitude of the gravitational field anywhere inside a hollow spherical planet?
What is the magnitude of the gravitational field at Earth’s center? What would the magnitude of the gravitational field be anywhere inside a hollow, spherical planet? zero N/kg. Newton viewed the curving of the path of a planet as being caused by a force actign on the planet.
What is the minimum size of a self-gravitating sphere?
[F]or bodies made mainly of rock, the minimum size to become a self-gravitating sphere is about 600km diameter; but, for bodies mainly made of ice, the minimum size is about 400km diameter.
When will a planet become a sphere?
Icy bodies start to become round under their own gravity at a certain mass. Rocky planets will take more. Liquids would form a sphere with miniscule mass as I assume gas proto-planets would be round as soon as they have enough gravity to be considered an “object.” $\\endgroup$ – Robert Cartaino Apr 1 ’14 at 20:10
What is the minimum mass for an object to be spherical?
$\\begingroup$The minimum mass to be spherical is a tiny fraction of a gram. A drop of water is spherical. You should ask what is the maximum mass that an object could be and still be non-spherical. This depends on how quickly it is formed, because if there is not sufficient time to cool, it will melt and become round.
Is it possible for a star to be perfectly spherical in shape?
This question is more complicated than it seems like it should be! There is no threshold mass or density beyond which an object becomes perfectly spherical; even supermassive stars are slightly oblong. The only exception is black holes, which are perfectly round up until you reach the quantum level.