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amjad-sh
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The force of gravity is F=mg.We know that that the gravitational force between Earth and object is F=MmG/h2(sqared).Can we say that mg=MmG/h2(sqared)?
amjad-sh said:Now put the stone on a table(the system is now:earth+table+stone).Does this cancel the reaction force of the stone on earth?
Yes. They are the same. For G = 6.67384e-011N.(m/kg)^{2}, M = mass of Earth = 5.97219e+024 kg, h = radius of spherical Earth = 6,371,000 meters, we get F = 9.8196 * m. So it gives the correct acceleration of gravity (9.8196 m/s^{2}) at the Earth's surface, ignoring centrifugal acceleration. (see https://en.wikipedia.org/wiki/Gravity_of_Earth section "Estimating g from the law of universal gravitation")amjad-sh said:The force of gravity is F=mg.We know that that the gravitational force between Earth and object is F=MmG/h2(sqared).Can we say that mg=MmG/h2(sqared)?
.Drakkith said:Certainly (as long as 'cancel' means 'opposes')
amjad-sh said:if this doesn't happen the summation of the internal forces will not end up to zero
As showed in the figure if you add the internal forces,all will be canceled except the normal force will remain.jtbell said:How do you figure that?
Yes, but this will lead that the summation of internal forces is not zero.Orodruin said:No, there is still a gravitational force on the Earth from the stone, it is a force pair with the gravitational force from the Earth on the stone, as required by the third law.
YES, YOU ARE RIGHT!jtbell said:Let's call your "normal force" F_{stone/table}. By Newton's 3rd law, there is also an F_{table/stone} which is equal in magnitude and opposite in direction.
The force of gravity is the force that pulls objects towards each other. It is dependent on the mass of the objects and the distance between them.
F=mg is the formula for calculating the force of gravity. F represents force, m represents mass, and g represents the acceleration due to gravity, which is approximately 9.8 m/s² on Earth.
The force of gravity is an inverse square law, meaning that as the distance between two objects increases, the force of gravity between them decreases. This is because the gravitational force is spread out over a larger area as distance increases.
The force of gravity between two objects is directly proportional to the product of their masses. This means that as the mass of an object increases, the force of gravity between it and another object also increases.
No, the force of gravity can vary depending on the mass and distance of the objects involved. For example, the force of gravity on Earth is stronger than the force of gravity on the moon due to the difference in mass and distance between the two objects.