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Vorbis
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This might sound like an unoriginal question but what is gravity? Why does the Earth and the sun and other planets have gravity? Does everything have gravity? What causes gravity?
Thanks ahead of time
Thanks ahead of time
Vorbis said:Why does the Earth and the sun and other planets have gravity?
Vorbis said:Well everything has mass so does that mean everything has its own gravity? How come that if I put a marble on a table it doesn't role towards me?
Bob_for_short said:The friction force is more strong than the gravity force in your case, that is why. H. Cavendish measured attraction of masses in a more clean experiment.
Bob.
No.Vorbis said:So The marble would role if the surface was extremely, impossibly smooth?
Vorbis said:This might sound like an unoriginal question but what is gravity? Why does the Earth and the sun and other planets have gravity? Does everything have gravity? What causes gravity?
Thanks ahead of time
Buckleymanor said:No.
You just ain't big enough in comparison to the Earth for the marble to be atracted to you..
The marble could be suspended on the end of a string to overcome most frictional forces but it's deflection towards you would be so minimal it would be very difficult to measure.
The Cavendish experiment used a mountain and some very sensitively mounted weights to measure the attraction of mass, and if memory serves me right it took quite a long time to set up the equipment.
Even then the deflection was minimal and had to be observed via a telescope I think.
fatra2 said:Mass causes gravity field
gmax137 said:No, that's not right. The presence of the Earth has no effect on the force between you & your marble. The force is much smaller than the force between the Earth & the marble, but that's not the point. The OP is right, there is a force between him & his marble, and the Cavendish experiment is a clever way of measuring it.
Difficult but not impossible. In general, that's pretty close to what Cavendish did.
The Cavendish experiment is routinely done in physics classes. It is done by measuring the attraction between two sets of weights, one set is large and the other is small. No mountains are involved. The weights are arranged in a torsional balance, what gets measured is the 'twist' induced by the gravitational force (and counteracted by the torsion of the twisting wire). Check google or wiki for a more detailed explanation with some graphics to make the setup more clear.
As far as the mountain goes, Cavendish used the result to calculate the mass & density of the earth. Maybe that's what you're trying to remember.
fatra2 said:Hi there,
When you talk about the Earth and the Sun's gravity pull, you have to understand Newton's third law. If the Earth pulls on you, you pull on the Earth. Therefore, you develop an gravitational pull on the objects around you.
Let's just make it clear: not only is the marble attracted to you by thee gravitational pull exerted by your ~75kg mass, but you are attracted to the marble by its ~5g mass.Vorbis said:If I weighed, let's say 10,000,000 tons, would the marble be attracted to me or am I just a confused child?
The Earth and the Sun have gravity because they both have mass. Gravity is a force that exists between any two objects with mass. The larger the mass, the greater the gravitational force.
Gravity is a force that pulls objects towards each other. This force is created by the mass of the objects and the distance between them. The larger the mass of an object, the stronger its gravitational pull. The closer two objects are, the stronger the gravitational force between them.
The planets revolve around the Sun because of the Sun's gravitational pull. The Sun's mass is much greater than that of the planets, so its gravitational force is strong enough to keep the planets in orbit. The planets also have their own gravitational pull, which helps to keep them in orbit around the Sun.
Objects fall towards the Earth because of the Earth's gravitational pull. The Earth's mass creates a gravitational force that pulls objects towards its center. This is why objects fall towards the ground when dropped from a height.
The force of gravity affects the Earth and other planets by keeping them in orbit around the Sun. It also helps to keep our atmosphere in place, which is essential for life on Earth. Gravity also plays a role in the formation and movement of tides on Earth. On other planets, the strength of gravity can vary depending on their mass and distance from the Sun.