How is acceleration possible if there is an everpresent equal+opp force?

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Discussion Overview

The discussion centers around the mechanics of acceleration in the context of a horse pulling a wagon, specifically addressing the apparent contradiction of equal and opposite forces as described by Newton's third law. Participants explore the implications of these forces on the acceleration of both the horse and the wagon, examining the roles of net forces and friction.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants question how acceleration is possible when the wagon exerts an equal and opposite force on the horse, suggesting that these forces would cancel each other out.
  • Others propose that acceleration occurs because the equal and opposite forces act on different objects, allowing for net forces to drive acceleration.
  • It is noted that the net force on the wagon is the force exerted by the horse minus friction, enabling the wagon to accelerate.
  • Similarly, the net force on the horse is described as the friction force between the horse's feet and the ground minus the force from the wagon, allowing the horse to accelerate forward.
  • A participant emphasizes that it is the net force that produces acceleration and that both forces are proportional to one another.
  • There is a suggestion that if the force of the horse on the wagon were equal and opposite to the frictional force on the wagon's wheels, there would be no net force and thus no acceleration.

Areas of Agreement / Disagreement

Participants express differing views on the implications of equal and opposite forces, with some asserting that they lead to cancellation while others clarify that they act on different objects, allowing for acceleration. The discussion remains unresolved regarding the interpretation of these forces in the context of acceleration.

Contextual Notes

Some assumptions regarding the nature of friction and the specific conditions of the scenario are not fully explored, leaving room for further clarification and discussion.

lamp23
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In the situation where a horse pulls a wagon, how is it possible for the horse to accelerate if the wagon is exerting an equal and opposite force? Wouldn't the forces cancel each other out?
 
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Acceleration is occurs when part or all of the equal and opposing force is a reaction to that acceleration.
 
lamp23 said:
In the situation where a horse pulls a wagon, how is it possible for the horse to accelerate if the wagon is exerting an equal and opposite force? Wouldn't the forces cancel each other out?
The equal and opposite forces act on different objects. The net force on the wagon is the force of the horse on the wagon less some small friction force on the wagon's wheels, so it accelerates. The net force on the horse is the large friction force between the horses feet and the ground driving it forward, less the smaller force of the wagon on the horse calculated above, so the horse also accelerates forward at the same forward acceleration of the wagon .
 
lamp23 said:
In the situation where a horse pulls a wagon, how is it possible for the horse to accelerate if the wagon is exerting an equal and opposite force? Wouldn't the forces cancel each other out?

PhanthomJay said:
The equal and opposite forces act on different objects. The net force on the wagon is the force of the horse on the wagon less some small friction force on the wagon's wheels, so it accelerates. The net force on the horse is the large friction force between the horses feet and the ground driving it forward, less the smaller force of the wagon on the horse calculated above, so the horse also accelerates forward at the same forward acceleration of the wagon .

Remember as PhantomJay pointed out, its the net force that produces the acceleration. Both of which are proportional to one another. If the force of the horse acting on the wagon was equal an opposite to the frictional force acting on the wagons wheels then there is no net force, hence no acceleration.
 
Nice post, Bugattti.
By the bye... I love your cowl. :biggrin:
 
Danger said:
Nice post, Bugattti.
By the bye... I love your cowl. :biggrin:

eh...my what? :confused: :smile:
 
bugatti79 said:
eh...my what? :confused: :smile:

Sorry, Pal... I thought that it was self-evident. I love the old Bugatti's, and one of their signature features was a honkin' long cowl (hood) with the flex-pipe headers sticking out.
 
Danger said:
Sorry, Pal... I thought that it was self-evident. I love the old Bugatti's, and one of their signature features was a honkin' long cowl (hood) with the flex-pipe headers sticking out.

Danger - I knew a fellow long ago that sold a Bugatti Kit for the handyman. Also, I apologize for the off topic comment - it won't happen again
 
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