Action and Reaction - I. Newton

AI Thread Summary
When standing on Mt. Everest, gravity causes a downward acceleration towards Earth, while according to Newton's third law, Earth experiences an equal and opposite force acting upwards. However, the Earth's massive mass results in an imperceptibly small acceleration in response to this force. The discussion highlights that while the force exerted by a person is significant, the resulting acceleration of Earth is negligible due to its enormous mass. The conversation also humorously suggests that future discussions might shift focus to "global acceleration" in the context of climate change. Overall, the interaction between a person's weight and Earth's mass illustrates fundamental principles of physics.
tkojemile
Messages
2
Reaction score
0
Hi,

I have for me a complex question! :(

If I get to Mt. Everest (let's say - highest place on Earth), then there is acceleration of my body towards the Earth - because of g - gravity force.

Now - question is does Earth have acceleration towards my body - as 3rd Isaac N. law would say!

And if it has - why?

Thanks for help
 
Physics news on Phys.org
Yes. The difference being, the acceleration on the Earth is negligible. Let's take f=ma, you exert, say, 800N (i.e. 80kg * 9.8ms-2) downwards. Likewise, the Earth now has a force 800N acting upwards. But, since that 800N is acting on 238083259285928234523kg of mass, the acceleration is just too small for anyone to care.

Maybe when global warming dies off, we'll move onto "global acceleration"?
 
dst said:
Maybe when global warming dies off, we'll move onto "global acceleration"?

Good one! Thanks for AW.
 

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

B Are frictional forces action forces or reaction forces?
Replies
14
Views
1K
I Newton's Third Law: Action & Reaction Along the Line Connecting Two Objects
Replies
5
Views
1K
I Extending Newton's laws -- Is the concept of force still defined?
Replies
35
Views
4K
B Why Is an Object's Weight Equal to the Force of Gravity It Experiences?
2
Replies
51
Views
4K
B What is the Absolute Value of the Normal force on a block on this wedge?
Replies
3
Views
1K
Analysis of a deformable body and Newton's 3rd Law
Replies
31
Views
2K
How Does Mass Influence the Reaction in Newton's 3rd Law of Motion?
Replies
9
Views
2K
Reaction torque in a traction system
Replies
10
Views
2K
Centripetal acceleration problem (box sitting on a table)
Replies
3
Views
1K
B General Relativity: Action & Reaction in Gravitation
Replies
15
Views
2K

Hot Threads

Recent Insights

Back
Top