Conceptual check: Newton's third law

AI Thread Summary
The discussion centers on the forces acting on a stationary, inflated rubber balloon. Air inside the balloon exerts an outward force on the rubber, while air outside applies a lesser inward force. According to Newton's third law, the force exerted by the air inside the balloon corresponds to an equal and opposite force exerted by the rubber on the air. Participants explore the concept of force pairs, emphasizing that the rubber must push back against the air inside. The conversation highlights the importance of understanding these interactions to grasp the principles of force equilibrium.
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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