Does an Apple's Gravity Affect Earth's Movement? | Exploring Physics Problems

In summary, the Earth's movement is often ignored in physics problems to make calculations easier for students, but it should be noted that an apple falling also exerts a gravitational pull on the Earth, causing a negligible acceleration.
  • #1
mtasquared
10
0
When an apple falls to the ground does it not exert some gravity of it's own on the Earth and thus shortening the distance it falls? Why is it always assumed the Earth does not itself move in physics problems?
 
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  • #2
mtasquared said:
When an apple falls to the ground does it not exert some gravity of it's own on the Earth and thus shortening the distance it falls?
Sure.
Why is it always assumed the Earth does not itself move in physics problems?
Estimate the Earth's acceleration due to the apple's gravitational pull. Then you'll see why it's ignored.
 
  • #3
mtasquared said:
When an apple falls to the ground does it not exert some gravity of it's own on the Earth and thus shortening the distance it falls? Why is it always assumed the Earth does not itself move in physics problems?

The idea of ignoring negligible calculations is to make it easier for students who are introduced to these concepts to make the calculations. However I think it should still be said to the students that the apple is causing the Earth to undergo a very very very small acceleration, so that they can be reminded that forces affect both objects.
 
  • #4
Thanks for replying!
 

1. Why do apples fall to the ground?

Apples, like any other object, fall to the ground due to the force of gravity. This force is constantly pulling objects towards the center of the Earth.

2. Does the mass of the apple affect how fast it falls?

Yes, the mass of the apple does affect how fast it falls. According to Newton's second law of motion, the greater the mass of an object, the greater the force needed to accelerate it. Therefore, a heavier apple will fall faster than a lighter one.

3. Why do apples sometimes fall faster or slower than other times?

The speed at which an apple falls is affected by several factors, such as air resistance, wind, and the angle at which it falls. For example, if an apple falls from a higher height, it will reach a greater speed due to the force of gravity acting on it.

4. Can an apple float instead of falling to the ground?

No, an apple cannot float instead of falling to the ground. This is because the force of gravity is still acting on the apple, pulling it towards the Earth's surface. The only way an apple can float is if it is in a liquid less dense than itself, such as water.

5. What would happen if an apple fell on a planet with no gravity?

If an apple fell on a planet with no gravity, it would continue to float in whatever direction it was initially moving. Without the force of gravity, there would be no pull towards the center of the planet, causing objects to float rather than fall to the ground.

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