What happens when you fire a gun in a zero gravity environment?

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Discussion Overview

The discussion centers on the behavior of a bullet fired from a gun in a zero-gravity environment, specifically considering the effects of air resistance and friction. Participants explore the implications of firing a gun without Earth's gravitational influence and the resulting motion of the bullet.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that the bullet will continue in a straight line after being fired, ceasing to accelerate once it leaves the muzzle, but will eventually slow down due to air resistance.
  • Others argue that the bullet cannot attain terminal velocity in the absence of gravity, as terminal velocity requires a balance of gravitational and frictional forces.
  • A participant notes that the bullet reaches its maximum velocity upon exiting the barrel and will subsequently decelerate until it stops due to air friction.
  • There is a suggestion that the bullet's path will remain straight, but it will not travel infinitely due to the effects of air resistance.

Areas of Agreement / Disagreement

Participants generally disagree on the concept of terminal velocity in this context, with some asserting it is not applicable without gravity, while others maintain that the bullet will slow down due to air friction. The discussion remains unresolved regarding the implications of firing a gun in a zero-gravity environment.

Contextual Notes

Limitations include assumptions about the nature of air resistance and the absence of gravitational forces, as well as the specific conditions under which the bullet is fired.

cooldood
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This is my first physics question (and hopefully not my last)

I've been wondering about what happens when you fire a gun in a situation with no gravity (or atleast no gravity of the Earth's) but when there is air and frictional forces present. People have tried to convince me that the bullet attains its terminal velocity and then continues in a straight line (infinitely)

Is this possible ? :confused:
 
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Welcome to PF, Cooldood.
The bullet will cease accelerating as soon as it leaves the muzzle (actually, a brief fraction of a second later due to residual pressure following it), and then indeed carry on in a straight line. The shooter will also be moved backward by the recoil force, which is equal to that carried by the bullet.

edit: By the time I got around to answering this, I forgot that I hadn't read the entire question. I'm at work, got interrupted part-way through, then finished without seeing the part about 'infinitely'. :redface: It will indeed slow down and eventually stop due to friction and compression forces, but it's path will be a straight line. Sorry, guys.
 
Last edited:
cooldood said:
This is my first physics question (and hopefully not my last)

I've been wondering about what happens when you fire a gun in a situation with no gravity (or atleast no gravity of the Earth's) but when there is air and frictional forces present. People have tried to convince me that the bullet attains its terminal velocity and then continues in a straight line (infinitely)

Is this possible ? :confused:
Not possible. Air friction keeps slowing down the moving body, until it stops.
 
Terminal velocity requires a balance of forces; that's not the case here. As long as air resistance (the only force) continues to act, the bullet will continue to slow down.
 
No, the term "terminal velocity" refers to the velocity where the force due to gravity (g, m*g, where g is about 9.8 m/s^2) is "balanced out" by the friction due to air (which is proportional to the speed of the bullet).
Hence, in the absence of gravity (and forces from e.g. from a rocket) there is no such thing as terminal velocity.

This means that the bullet will have reached its maximum velocity when it leaves the barrel of the gun, then it will just slow down due to friction until it stops.
 
Thanks a lot everyone :)
 

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