Zero Force Propulsion: A Futuristic Concept?

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Discussion Overview

The discussion revolves around the concept of zero force propulsion for vehicles, exploring theoretical possibilities of maintaining constant velocity without continuous external force. Participants consider implications for efficiency, environmental impact, and practical applications, while addressing the challenges posed by real-world forces such as friction and air resistance.

Discussion Character

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

Main Points Raised

  • Some participants propose the idea of negating net external forces to maintain constant velocity, suggesting that once a vehicle is accelerated, it could theoretically continue moving without additional force.
  • Others argue that achieving zero force propulsion is impossible due to the inevitability of resistive forces like friction and air resistance, which require continuous acceleration to counteract.
  • A participant suggests using a vacuum tube and magnetic repulsion to reduce resistive forces, potentially allowing for more efficient travel.
  • Another participant references Newton's First Law, emphasizing that objects in motion require no external force to maintain constant speed in an ideal scenario devoid of resistive forces.
  • Some contributions highlight the impracticality of achieving 100% efficiency in real-world conditions, noting that vehicles will always need to account for forces acting against them.
  • There is mention of historical concepts, such as Heinlein's idea for a lunar transit system, which involves using magnetic repulsion and orbital velocity.

Areas of Agreement / Disagreement

Participants generally disagree on the feasibility of zero force propulsion, with some supporting the theoretical concept while others emphasize the limitations imposed by real-world forces. The discussion remains unresolved, with multiple competing views presented.

Contextual Notes

Limitations include assumptions about ideal conditions versus real-world physics, as well as the dependence on definitions of force and propulsion. The discussion acknowledges the presence of resistive forces that cannot be entirely eliminated.

Vincit
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What if we don't NEED to use any force whatsoever to propel a vehicle? What if we could negate the net external force and just keep the vehicle going with a constant velocity with the appropriate magnitude? But what could we use to propel the vehicle at any given time and not add any other force as it is moving with a constant velocity(Also, this could stop speeding:D) - as we DO need to brake on the road:P Something not hazardous to the environment, so pollution isn't a problem.. we need something particulate and with a high enough magnitude - any suggestions?

This is all seems too futuristic right now, but just an idea.
 
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I like your thinking outside of the box, but I don't really get your first sentence. How are you going to accelerate from a stopped position. No force = no acceleration.
 
Sorry i must have worded it wrong. I mean, we need to use force to accelerate the vehicle - but then we could stop the external force, thus leaving a constant velocity. there's a lot of gaps, but i think we can work through it:)
 
Vincit said:
Sorry i must have worded it wrong. I mean, we need to use force to accelerate the vehicle - but then we could stop the external force, thus leaving a constant velocity. there's a lot of gaps, but i think we can work through it:)

Drive in a vacuum?
 
I believe that it's impossible for a car to be 100% efficient, meaning that you will not be able to negate slowing forces on a car, which means you will always need some form of acceleration :(

EDIT: Or take Nabeshin's idea haha
 
Yes, nabeshin haha
 
Nabeshin said:
Drive in a vacuum?

Yup, as long as we have to deal with gravity and atmosphere, we're going to need a Force to keep constant velocity.
 
the question is - what is that force?
 
Vincit said:
Sorry i must have worded it wrong. I mean, we need to use force to accelerate the vehicle - but then we could stop the external force, thus leaving a constant velocity. there's a lot of gaps, but i think we can work through it:)
That's just another way of saying Newton's First Law of motion: objects require no external force to continue motion at constant speed.
 
  • #10
Have the vehicle travel in a tube in which there is a vacuum .. floating due to magnetic repulsion above current loop superconductors .. at the end of the trip, decelerate the vehicle with an electrical generator and Lenz's Law, so you get back some of the energy that was initially used to accelerate it.
 
  • #11
mikelepore said:
Have the vehicle travel in a tube in which there is a vacuum .. floating due to magnetic repulsion above current loop superconductors ..
Once you reach orbital velocity you don't even need the magnetic repulsion for floating. At least, that was Heinlein's idea for a transit system on the moon.
 
  • #12
onto something
 
  • #13
you need a force to accelerate a mass. and for a car like transport you need to cycle slowdown and go. because you are going allover the town. a futuristic system of cars traveling on rails merging and branching had already been tested.(powered by elctricity)
the problem with that is cost, just like those fancy magnetically lavitated trains which do have special uses but not general.
 
  • #14
In an imaginary world completely devoid of all resistive forces it is reasonable to assume that an object can continue moving with a constant velocity without an external force.We live in the real world where friction and air resistance are present.We can reduce these forces but not to zero.When an object moves with terminal velocity there are still forces acting on it but the resultant is zero.
 
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