What happens to free body diagrams when breaking through a wall?

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Discussion Overview

The discussion revolves around the dynamics of free body diagrams in the context of breaking through a wall. Participants explore the forces acting on both the person exerting the force and the wall, considering scenarios where the wall either breaks or remains intact. The conversation touches on fundamental principles of physics, including Newton's laws of motion.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant describes the forces acting on their hand when pushing against a wall, noting the normal contact force and the force required to maintain position.
  • Another participant agrees with the initial analysis, stating that Newton's third law does not imply equilibrium in this context.
  • A different participant suggests that the discussion conflates Newton's first and second laws, emphasizing that the second law pertains to net forces on a single body.
  • One participant questions the forces acting on them when the wall breaks, proposing that their hand experiences a normal contact force and their own pushing force, while also inquiring about the dynamics of pushing against air.
  • There is a suggestion that when pushing air, the air molecules do not experience a counteracting force, leading them to move away, although this remains uncertain.

Areas of Agreement / Disagreement

Participants express differing interpretations of the forces involved, particularly regarding the application of Newton's laws. There is no consensus on the implications of breaking through a wall versus pushing against air, and the discussion remains unresolved.

Contextual Notes

Some assumptions about the forces involved and the conditions under which they apply are not fully explored, leading to potential gaps in understanding the dynamics at play.

Who May Find This Useful

Individuals interested in mechanics, physics students, and those exploring the application of Newton's laws in practical scenarios may find this discussion relevant.

sgstudent
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When I exert a force, I will experience an equal and opposite force on two mutual bodies. However, when I break through a wall how do the free body diagrams of my hand and the wall? When the wall doesn't break, the forces on the hand is normal contact force on my hand from the wall and a force pushing it to make it stay st that position. As for the wall, its a force that I exact on it by my hand and also a force to balance the exerted force on the wall.

But when dealing with the breaking wall case, I'm unsure what happens. Thanks for all the help!
 
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Your analysis is correct in both cases: the case where the wall breaks and the case where the wall doesn't break. The third law doesn't imply or require equilibrium.
 
Seems you are combining the first and the second laws. It's like when you push an object on a frictionless surface, the force you apply on the object is equal to the force the object applies on your hand. If I got you correctly, according to your analysis, your hand ( and the object) should not accelerate.

Second's law is about net forces on the "same body". When you break through the wall, the wall exerts a force on your body, your weight and also your the floor ,through your shoes, exerts forces. The combination these forces determines your motion.
 
So when the wall breaks the forces on me is the normal contact firce by the wall on me and my own pushing force on myself? Then for the wall its my exerted force with less pushing force back on my exerted force? Then what happens when I push air? I apply a force in it so Teresa another force on me so I have to apply some force on myself to counteract it. While for the air molecules they don't have that counteracting force so they simply move away? Are these assumptions right? Thanks for all the help!
 

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