# What is Force fields: Definition and 24 Discussions

In speculative fiction, a force field, sometimes known as an energy shield, force shield, force bubble, defence shield or deflector shield, is a barrier made of things like energy, negative energy, dark energy, electromagnetic fields, gravitational fields, electric fields, quantum fields, plasma, particles, radiation, solid light, or pure force. It protects a person, area, or object from attacks or intrusions or even deflects energy attacks back at the attacker. This fictional technology is created as a field of energy without mass that acts as a wall, so that objects affected by the particular force relating to the field are unable to pass through the field and reach the other side, are deflected or destroyed. This concept has become a staple of many science-fiction works, so much that authors frequently do not even bother to explain or justify them to their readers, treating them almost as established fact and attributing whatever capabilities the plot requires.
The ability to create forcefields has become a frequent superpower in superhero media.

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1. ### I Why Must Pure Force Depend on 4-Velocity?

Disclaimer: Please read in the following formulas ##E/c^2## instead of ##m##, because W. Rindler used relativistic mass, what might be confusing with today's usage of the term "mass". I am reading the chapter "38. The formal structure of Maxwell's theory" in Wolfgang Rinder's book "Introduction...
2. ### Slightly More Plausible Barriers Than Force Fields

I am contemplating writing a science fiction story involving flexible barriers that can be erected in a very short time. Force fields are pervasive in science fiction, but from what little I've read, they're not very plausible. Is there a flexible material, or class of materials, that...
3. ### I Force fields in curvilinear coordinate systems

I am trying to solve problems where I calculate work do to force along paths in cylindrical and spherical coordinates. I can do almost by rote the problems in Cartesian: given a force ##\vec{F} = f(x,y,z)\hat{x} + g(x,y,z)\hat{y}+ h(x,y,z)\hat{z}## I can parametricize my some curve ##\gamma...
4. ### Why are central force fields irrotational and conservative?

In Mathematical Methods for Physicists, 6th Edition, page 44, Example 1.8.2, the curl of the central force field is zero. 1. Why are central force fields irrotational? 2. Why are central force fields conservative? Any help is much appreciated...
5. ### Unlimited Possibilities: Replicating ID4's Force Field

What is the closest thing we can come up with that does the same thing as ID4's force field?Assuming we have unlimited energy, unlimited space and somehow won't kill anyone in the process.
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### I Experimentally measure gravitational force

Can we experimentally measure the very weak gravitational force between two objects just like we can detect magnetic field lines by a deflecting compass.
7. ### Problem on a question about the gravitation potential

Hello everyone 1. Homework Statement In the solution of a question, regarding the gravitational force fields and gravitational potential when the mass is inside Earth (where the height of the mass is lower than the radius of earth), the step where we take the integral of the force in order to...
8. ### What amount of energy is needed to make a field of plasma?

How much energy would be required to generate a spherical field of plasma using an EM field? I have heard that EM fields can excite atoms in the air to create plasma- however, this may be incorrect. If correct, how much energy would be needed and would it fry anything inside because of the...
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### I Question about the formal definition of conservative force

So, I was reading the mathematical description of a conservative force o wikipedia : https://en.m.wikipedia.org/wiki/Conservative_force and at the line "Many forces (particularly those that depend on velocity) are not force fields. In these cases, the above three conditions are not...
10. ### Is Gravitational Force conserved at the origin (r=0)?

I know gravity is a conservative force field and can be treated as such for all intents and purposes, but I was just thinking that in order to show that a vector field is conservative that vector field must be defined everywhere (gravitational force field is not defined at r=0). I was thinking...
11. ### Are force fields deformed by length contraction?

Imagine you have an electron traveling at high speeds... would you expect it´s EM field to be contracted following the Lorentz transformations?? If the answer is no, please explain why fields and their shape don´t deform when space-time does. How they retain their shape in a space that is not...
12. ### Gravity: Conservative or Non-Conservative?

We generally take the force of gravity to be conservative, but what if the source of gravity is moving through space? Then the force would only be conservative relative to the source, correct? As another example, consider someone in a balloon ascending with constant speed relative to earth...
13. ### Force fields and law of conversation of energy

Why aren't force fields such as magnetic, electric and gravitational fields considered as a violation to law of conversation of energy?? :confused:
14. ### Grade 12 Gravitational Force Fields Questions.

[b]1.Nasa fires a 1 tonne space probe, from a stable orbit of altitude 13,620km using a giant rail gun. The rail gun provides the probe with 9.97165*10^10 J of additional kinetic energy. Determine if the probe has enough velocity to escape the Earth's gravity well. The Earth's mass and radius...
15. ### Why the carrying force fields must be the fields of Boson particles?

Please teach me this: Why carrying force particles must be Bosons and matter particles must be Fermions?By the way,why do we concentrate on Gauge Symmetries?Is it correct that is because the Gauge theories lead to vector Bosons that carrying forces? Thank you very much for your kind helping.
16. ### Discrete Force Fields: Quantized or Infinite?

If the universe is http://en.wikipedia.org/wiki/Digital_physics#Wheeler.27s_.22it_from_bit.22", then would force fields be quantized (not extend to infinity)? Must force fields extend infinitely for conservation of energy (transmission of em waves)?
17. ### Conservative force fields and line integrals

Conservative vector fields and line integrals Homework Statement A particle is subject to a force F defined by F\left( x,y \right)=\left(\begin{array}{c} y^{2} \\ 2xy \end{array}\right). The particle moves in a straight line C from (-1,2) to (1,3).[a] Calculate the work done by the force F as...
18. ### Force fields, vectors, and work (mostly just confused by notation)

Homework Statement Consider a force field F = c(iy - jx). From the force field calculate the work required to move a particle from the origin to the point 2i + 4j without acceleration along the two different paths: From the origin to 2i then to 2i + 4j From the origin to 4j then to 2i + 4j...
19. ### Finding a Plane with Zero Circulation for a Given Vector Field

Homework Statement Suppose that f is a vector field such that curl f=(1,2,5) at every point in R^3. Find an equation of a plane through the origin with the property that \oint_{C}f dot dX = 0 for any closed curve C lying in the plane. Homework Equations...
20. ### Star Trek Nerd: What are force fields and why dont we have them?

sorry about the fantasy factor here guys, but having a kind of barrier that can repel mass and be "mass less" without having any visible infrastructure would be quite valuable. so the question is: What are force fields? (like the ones in star trek) what would they compose of? and what keeps...
21. ### Exploring Force Fields in Sci-Fi Writing

I am an aspiring science fiction writer. By training I'm a psychologist, so my knowledge of physics is somewhat limited. (I like understatement.) In the story I am currently writing, I have a military base surrounded by a force field, which I assume would be some sort of EM field. If I set up my...
22. ### Conservative force fields

hello I am having a few troubles on these two force field problems, determining whether that are conservative or not. F = (x, y, z) / (x^2 + y^2 + z^2)^3/2 and F = (x, y, z) / (x^3 + y^3 + z^3) i know that when the force is independent of the path then the force is said to be...
23. ### Understand Force Fields: Store and Release Energy?

This question is more regarding terminology than anything. It's from one of my assignments. The question is can you store energy in and release energy from a force field? I don't really understand what is being asked. I know you can store potential energy in objects in the force field, and...
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### Calculating Work of Force Field F(x,y) on Particle Moving Along Parabola y=x²

Dose someone know how to do this... Find the work done by the force field F(x,y) = x sin j + yj on particle that moves along the parabola y = x² from (-1,1) to (2,4). With thanks, Alex