Does a Bullet Speed Up After Being Fired?

[CharlesF]

Does a bullet speed up after leaving the gun?

 

[LURCH]

If it's fired downhill in a vacuum, yes. Otherwise, no.

 

[russ_watters]

We got this exact question a month or so ago - where is this coming from, Charles?

 

[CharlesF]

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.

 

[rcgldr]

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.