- #1
Flor
- 11
- 0
Why does the Earth attract the apple and the apple at the same time does not attract the Earth (the Earth does not move to the apple)?
Why Does an Apple Fall to Earth, But Earth Doesn't Fall to the Apple?
In summary, the apple does not attract the Earth because the Earth's mass is much greater than the apple's and the gravitational force is in opposite directions.
- #2
Rear Naked
- 48
- 0
It does :-)An apple is so much less massive than Earth, so its effects are negligible go unnoticed.
The forces of attraction will be equal and opposite. However, you must take inertia into account. The inertia of the Earth is very great, but the ineria of the apple is small. The force is strong enough to move the apple, but not strong enough to noticeably move the Earth.
The forces of attraction will be equal and opposite. However, you must take inertia into account. The inertia of the Earth is very great, but the ineria of the apple is small. The force is strong enough to move the apple, but not strong enough to noticeably move the Earth.
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- #3
Flor
- 11
- 0
I know, but is it observable? Or what is the best way to explain what we observe? I see an apple falling down :)
- #4
Rear Naked
- 48
- 0
It is inertia.
Push an apple across a desk. Now try to push a car using that same force.
How do you know the Earth is not moving up towards the apple?
Push an apple across a desk. Now try to push a car using that same force.
How do you know the Earth is not moving up towards the apple?
- #5
HallsofIvy
Science Advisor
Homework Helper
- 42,989
- 975
That's because you are standing on the Earth and are moving along with it. The Earth does not move relative to you.
Try this experiment instead- climb up into an apple tree and, as the apple falls, let go of the tree and fall with it. You will see that the apple does not move (relative to you) while the Earth is moving very rapidly toward both you and the apple!
- #6
Flor
- 11
- 0
Is it because the intensity of gravitational field (g) of Earth is much bigger than the intensity of gravitational field of an apple? I can give you another question - what happens if the Earth radius will expand for example 1 x 10^30 times? Then the Earth will fall on apple! Is it true? :)
- #7
Rear Naked
- 48
- 0
Gravitational force doesn't depend on the radius, only mass.
- #8
Rear Naked
- 48
- 0
m2 = mass of apple
r = distance between them
G = gravitational constantThe magnitude of force F will be the same for both objects, only in opposite directions.Everything is the same...except mass (ie. inertia)
If the mass of the apple is increased an incredible amount, we then might observe the effects.
- #9
chrisbaird
- 610
- 5
Flor said:
No, the force is the product of both masses, and they both feel the same force (action and reaction forces equals). Think of F = m a for the apple the for the earth, where F is the same for both. For the earth, m is huge, so the acceleration a must be tiny to keep F constant and equal to the F that the apple feels.
- #10
- 32,820
- 4,715
Flor said:
You may want to start by reading this FAQ
https://www.physicsforums.com/showthread.php?t=511172
Zz.
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1. How does the gravity of an apple compare to the gravity of the Earth?
The gravity of an apple is significantly less than the gravity of the Earth. The Earth's gravity is approximately 9.8 meters per second squared, while the average apple has a gravity of about 0.2 meters per second squared. This means that the Earth has almost 50 times more gravitational pull than an apple.
2. Why do apples fall to the ground when dropped?
Apples, and all objects, fall to the ground when dropped because of the Earth's gravitational pull. Gravity is a force that attracts objects towards each other. The Earth is much larger and has more mass than an apple, so it exerts a greater gravitational force on the apple, causing it to fall.
3. Can an apple's gravity affect the Earth's orbit?
No, the gravity of an apple is too small to have any significant impact on the Earth's orbit. The Earth's orbit is determined by the gravitational pull of the sun and other large objects in our solar system. The apple's gravity is negligible in comparison.
4. Is the gravity of an apple affected by the Earth's rotation?
Yes, the Earth's rotation does have an effect on the gravity of an apple. The faster an object rotates, the weaker its gravitational pull becomes. This is known as the centrifugal force. However, the effect is so small that it is not noticeable in everyday situations.
5. How does the gravity of an apple contribute to the Earth's overall gravity?
In terms of the Earth's overall gravity, the gravity of an apple is insignificant. The Earth's gravity is determined by the mass and density of the entire planet, not just one small object like an apple. However, the Earth's gravity does have a slight influence on the apple's gravity, as it is affected by the Earth's mass and rotation.
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