Does an Apple’s Gravity Influence Earth’s Movement?

AI Thread Summary
An apple falling to the ground does exert a gravitational pull on the Earth, theoretically shortening the distance it falls. However, this effect is negligible compared to the Earth's mass, making it impractical to consider in physics problems. The simplification of ignoring the Earth's movement helps students focus on fundamental concepts without overwhelming them with complex calculations. Nonetheless, it's important to acknowledge that both the apple and the Earth experience gravitational forces that affect each other. Understanding this interaction can enhance comprehension of gravitational principles.
mtasquared
Messages
10
Reaction score
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?
 
Physics news on Phys.org
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.
 
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.
 
Thanks for replying!
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »

Thread 'Average velocity as a weighted mean'

Hello everyone, Consider the problem in which a car is told to travel at 30 km/h for L kilometers and then at 60 km/h for another L kilometers. Next, you are asked to determine the average speed. My question is: although we know that the average speed in this case is the harmonic mean of the two speeds, is it also possible to state that the average speed over this 2L-kilometer stretch can be obtained as a weighted average of the two speeds? Best regards, DaTario
View full post »

Thread 'Newton's first law?'

Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
View full post »

Similar threads

An apple falls from a tree, Does the moon move as a result?
Replies
2
Views
1K
Why Is It That An Apple Will Fall To The Earth?
Replies
9
Views
3K
Falling apple inside a space centrifuge
Replies
11
Views
2K
How long would it take for an apple to fall to the earth
Replies
5
Views
2K
B Why Is an Object's Weight Equal to the Force of Gravity It Experiences?
2
Replies
51
Views
4K
Why did Newton think the apple was pulled, not pushed?
Replies
5
Views
2K
I Normal force and details of the Earth holding up an object
Replies
12
Views
2K
I Source of Gravity of heavy mass as per GTR
Replies
14
Views
2K
Did Newton Actually Discover Gravity with an Apple?
Replies
2
Views
3K
B About verification on Kinetic energy and work
Replies
16
Views
2K

Hot Threads

Recent Insights

Back
Top