Newton's third law and a box push

Click For Summary

Homework Help Overview

The discussion revolves around Newton's third law, specifically addressing the scenario where a person pushes a box and the box exerts an equal and opposite force on the person. Participants explore how this interaction allows the person to still move the box.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants question how the forces involved allow for movement, particularly focusing on the role of the Earth's reaction to the person's force. There are discussions about the forces acting on both the person and the box, as well as the implications of these forces on movement.

Discussion Status

The discussion is ongoing, with participants expressing confusion and seeking clarification. Some have offered insights into the interactions between the forces, while others are still grappling with the concepts. There is a sense of progress as participants begin to understand the relationships between the forces involved.

Contextual Notes

Participants are navigating the complexities of Newton's third law and its implications in a real-world scenario, including the influence of the Earth in the force interactions. The discussion reflects a mix of understanding and uncertainty regarding these fundamental physics concepts.

mk876
Messages
6
Reaction score
0

Homework Statement



I just don't understand how to describe how, if a person pushes on a box and the box exerts an exactly equal but opposite force on the person that the person is still able to move the box...

Homework Equations



n/a

The Attempt at a Solution



n/a
 
Physics news on Phys.org
What about the feet of that person ?
 
So the feet of the person are meant to absorb the force of the box?
 
So what is there beneath the feet of the person ?

Maybe if you drew a very simple drawing of the situation it will help greatly.
 
The earth.

I drew a picture and the forces are the force of the person on the box, the force of the box on the person, the force of the person on the Earth and the force of the Earth on the person (not including the earth/box forces).

So the forces acting on the person are that of the box and that of the earth...
 
mk876 said:
So the forces acting on the person are that of the box and that of the earth...

Ok, but it's more correct the other way round: the forces acting on the box and on the Earth are the same that those the person exerts.
 
:( I'm confused.
 
mk876 said:
:( I'm confused.

Don't worry. I think you already got the situation correctly.
 
Ohh so are you saying the Earth will absorb the force of the box and so the person is able to move it?
 
  • #10
mk876 said:
Ohh so are you saying the Earth will absorb the force of the box and so the person is able to move it?

Think about a slightly different situation.

The person acts like a spring, pushing with a force F at one end and with the same force F at the other end.
The Earth and the box are then pushed by those Forces.
Since the Earth is very big, it will barely move at all.
But, the Earth is accelerated as well by a very very small quantity.

So you have 2 pairs of forces.
At one end of the spring, the earth-spring (action-reaction), on the other side spring-box (action reaction).
 
  • #11
Ohhh alright I think I understand a lot better now. Thanks for helping me out :D
 

Similar threads

Newton's Third Law for book on a table
  • · Replies 8 ·
Replies
8
Views
4K
Blowing Into Your Own Sail
  • · Replies 25 ·
Replies
25
Views
2K
Newton's Third Law: Acceleration of box and worker
  • · Replies 2 ·
Replies
2
Views
5K
Truck carrying a box, friction problem
  • · Replies 10 ·
Replies
10
Views
5K
Two Questions on Newton Law Problems
  • · Replies 5 ·
Replies
5
Views
2K
Newton's law problem: Helicopter lifting a box with a rope
  • · Replies 5 ·
Replies
5
Views
3K
What is the ranking of forces in a problem on ranking forces?
  • · Replies 8 ·
Replies
8
Views
2K
Newton's third law: Rower makes boat move forward
  • · Replies 2 ·
Replies
2
Views
6K
Friction problem (pushing a box)
  • · Replies 3 ·
Replies
3
Views
4K
Understanding Newton's Third Law in Action: A Truck Pushing an SUV
  • · Replies 4 ·
Replies
4
Views
2K