Conceptual check: Newton's third law

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SUMMARY

The discussion centers on Newton's Third Law as applied to a spherical rubber balloon inflated with air. The air inside the balloon exerts an outward force on the rubber, while the air outside applies a lesser inward force. This interaction exemplifies action-reaction force pairs, where the force exerted by the air inside the balloon corresponds to an equal and opposite force exerted by the balloon's rubber on the air. The participants explore the complexities of these forces, emphasizing the necessity of understanding both internal and external pressures in this scenario.

PREREQUISITES
  • Understanding of Newton's Third Law of Motion
  • Basic knowledge of pressure and force concepts
  • Familiarity with the properties of gases and their behavior in enclosed spaces
  • Concept of action-reaction force pairs
NEXT STEPS
  • Study the principles of fluid dynamics and pressure differentials
  • Explore practical applications of Newton's Third Law in real-world scenarios
  • Investigate the behavior of gases under varying pressure conditions
  • Learn about the mechanics of elastic materials and their response to internal and external forces
USEFUL FOR

Students of physics, educators teaching Newton's laws, and anyone interested in the mechanics of gases and elastic materials will benefit from this discussion.

Callista
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Homework Statement


A spherical rubber balloon inflated with air is held stationary, with its opening, on the west side, pinched shut. (a) Describe the forces exerted by the air inside and outside the balloon on sections of the rubber.

Homework Equations


?

The Attempt at a Solution


upload_2019-3-10_15-20-41.png

The air particles inside the balloon will push outwards on the rubber perpendicular to the surface. The air outside the rubber will push against the rubber perpendicular to the surface, and to a lesser degree. What I can't figure out is what WOULD be the matching force on each the air pushing in and the air pushing out.

Maybe the balloon rubber pushing against the air?
 

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Callista said:

Homework Statement


A spherical rubber balloon inflated with air is held stationary, with its opening, on the west side, pinched shut. (a) Describe the forces exerted by the air inside and outside the balloon on sections of the rubber.

Homework Equations


?

The Attempt at a Solution


View attachment 240051
The air particles inside the balloon will push outwards on the rubber perpendicular to the surface. The air outside the rubber will push against the rubber perpendicular to the surface, and to a lesser degree. What I can't figure out is what WOULD be the matching force on each the air pushing in and the air pushing out.

Maybe the balloon rubber pushing against the air?
yes, if the air inside pushes outward on the inside face of the balloon, then the inside face of the balloon must push inward on the inside air. That is one force pair. But wait, there is another. What is it??
 

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