Does a Bullet Speed Up After Being Fired?

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Discussion Overview

The discussion centers around whether a bullet continues to speed up after being fired from a gun, exploring the effects of external forces such as gravity and drag. Participants also relate this question to personal observations about acceleration in vehicles and sports equipment.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant suggests that a bullet can speed up if fired downhill in a vacuum, implying that external conditions affect the bullet's motion.
  • Another participant recalls a previous discussion on the same topic, indicating that this question has been raised before.
  • A participant shares a personal experience with their van, noting a perceived continued acceleration when changing gears, which leads to a broader contemplation about the behavior of bullets and other projectiles.
  • It is proposed that once a ball leaves a bat or club, it no longer accelerates and begins to decelerate due to drag, contrasting with the initial motion of a bullet.
  • A participant mentions that the pressure from the gun may still act on the bullet for a brief moment after it exits the barrel, but this effect is short-lived.
  • Another participant discusses how sensations of acceleration in vehicles can be misleading, suggesting that perceived acceleration may not reflect actual changes in the center of mass.

Areas of Agreement / Disagreement

Participants express differing views on whether a bullet can speed up after being fired, with some suggesting conditions under which it might and others asserting that it does not. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference personal experiences and observations, which may introduce subjective interpretations of acceleration and motion. The discussion also touches on the effects of external forces like drag and gravity, but these concepts are not fully explored or agreed upon.

Who May Find This Useful

Individuals interested in the physics of motion, projectile dynamics, and the effects of external forces on moving objects may find this discussion relevant.

CharlesF
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Does a bullet speed up after leaving the gun?
 
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If it's fired downhill in a vacuum, yes. Otherwise, no.
 
We got this exact question a month or so ago - where is this coming from, Charles?
 
I was driving my van the other day and i noticed that when i pressed the clutch into change to second gear the van seemed to continue accelerrate, with nothing powering it, just for maybe 1 second(or perhaps i imagined it).

That got me thinking about other things like bullets. Also does a cricket ball accelerate away from the bat with nothing pushing it, surely it can't get to it's return speed instantly.
 
In the case of a gun, there's still some pressure just as the bullet leaves the barrel, but this is a very short distance.

Once a ball leaves a bat, golf club, ... it no longer accelerates, and starts decelerating because of drag immediately.

In the case of a van, the suspension relaxing after acceleration mave give a rider a sense of continued acceleration, but the center of mass isn't accelerating. Sometimes the lack of deceleration force felt when braking then releasing the brakes, and car body pitch can give a false sense of acceleration as well.
 

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