But you still generally call an acceleration that results in the amplitude of the velocity decreasing (i.e. an acceleration opposite to the current velocity) a deceleration.
I’m not saying that a deceleration is an incorrect term, I’m just saying that accleration is a correct term. 
…i love this forum’s ability to carry a tangent…
So, nobody’s tested the rockets underwater in Source yet to see if it slows similarly… hmm. When in doubt, compare expectations with reality.
In reality, I would expect a change from air-to-water to detonate it, with sudden negative acceleration.
I would expect a launch in the water to accelerate more slowly, and reach a lower peak velocity, to the degree a circling projectile would expend all its fuel more easily (whence it becomes a sinking dud… or maybe a dumb bomb for when it hits bottom).
I would lastly expect a rocket to do just fine when launched into the air from under the water.
Another interesting possibility is for the targeting laser to reflect downward from the surface of the water if you aim at a shallow angle. 48.6 degrees is the critical angle of total internal reflection from water to air, which is conveniently near 45 degrees to simplify calculation and the ability of a user to know when to expect their laser to bounce. Also convenient is the fact that water is always on a horizontal plane. Another minor detail worthy of this thread may be the refraction encountered by this laser as it passes through the surface of water, shifting the dot.
Impact causes deceleration, isn’t it? Then inertia causes the release of energy (kinetic energy is converted to heat), and BOOM, everything explodes. Of course, deceleration caused by gravity wont cause the rocket to explode, but it’s a different story.
Uh…yeah but thats not what causes the RPG to explode. In the point nose of the RPG round is an impact detonator. When it hits an object the impact detonator actually needs to be crushed before it sends an electrical signal along a path of the outside of the round to the back detonating a primer. It is the actual physical impact and not deceleretion that causes it to explode. Insurgents in Iraq thought our Bradley Fighting Vehicles had force fields because when they shot them with RPG’s the reactive armor tiles blew up and fell off leaving no visible damage. They did all sorts of things to try to defeat our “force field”. One of which was putting copper wire around the RPG round. All this did was block the electrical signal from the impact detponator to the primer. It would just hit the Bradley with a thud and not detonate.
Hey, you’re the expert! However, technically crushing is caused be deceleration of the adjacent particles, it’s like a chain reaction. If there wasn’t deceleration and inertia, there wouldn’t be an impact, it’s a matter of how you define and understand things (yep, alway defend your statement till the end ;P).
You can’t just smack ‘ly’ onto the end of a random verb or adjective and call it a real word, nor expect people to understand what the hell you’re on about. You can argue that the same logic that applies to other adverbs works in this case and you’d be right, but that doesn’t make it any easier to understand. Slowingly isn’t a recognised word. It just sounds like you meant slowly.
As for HL2’s rockets, if I remember correctly you couldn’t fire them underwater, nor did they explode when they hit the water when fired from above.
As a small suggestion, I’d love it if, when you threw a grenade or other explosive underwater and it detonated, it would create a tall plume of water. It was present to a small extent in HL2 but it looked cheap, and only worked when you threw rollermines in the water. If I remember right, you could throw a grenade into the water and it would just explode, instead of blasting water into the air.
Hence why I mentioned the impact detonator. But it really doesn’t measure acceleration per se, or it would detonate by sudden changes of gravity or other forces that would decelerate it without deforming.
But I see you got the point already, so there really wasn’t much point in me writing this. But these are the Black Mesa Forums after all and this thread is all about details. :3
Fixed - I think his statement was perfectly understandable. It just sounded like he was stoned-posting, and I have no reason to believe that this wasn’t the case 
Sure thing . I’ll try to be more specific next time .
Like whoah, that’s a subvertingly deceptive take on things.
Well, I couldn’t find an adverb to express what I needed it to. If you have a better word than slowingly, be my guest. If you can’t think of any, accept the fact it must be assimilated into English.
(Resistance is futile, especially considering the lexical distinctiveness is purely of its own.)[/size]
But now we’re ignoring the point. Literally, the point of the detonator hitting water at a high velocity.
If you jump off of a bridge, you will break bones. If you skydive without a parachute, you will splatter as on concrete. The speed of a rocket-propelled grenade is high enough for water to smash it in.
The Half-Life 2 launcher resembles the AT4, which has a muzzle velocity of 285 m/s. The Half-Life 1 launcher resembles the SMAW, which has a muzzle velocity of 220 m/s. A skydiver has a terminal velocity of only 56 m/s.
One may argue that entering the water at a shallow descent would lessen the effect of this. In that case, the friction on the side of the projectile would be expected to bring it sharply into a nosedive… for the same result.
I’m not denying that it follows the same rules as other adverbs, but its lack of basis in accepted English makes its meaning elusive. What you’re trying to describe would be better suited as a description rather than a single word. But by all means try and popularise ‘slowingly.’ Stranger things have happened.
Wouldn’t have thought it would nosedive. It would simply skim, and bounce off the surface if it’s travelling that fast. At that speed, water might as well be concrete, which does support the fact that water would easily cause enough damage to set off the RPG detonator.
Hmm, you’re probably right about the skim…
But the fin, maybe, would do enough to drag it in?
Either way, that projectile won’t be making a clean splash as it dives into the water. (And I doubt the team would bother skipping rockets across c2a5) 
Probably way too late for this. But I figure it would be cool to watch a building get obliterated by an airstrike during Surface Tension.
Now we wait…
I’d love seeing some freaky weather effects in Xen. Alien rain, anyone?
I think it just might be too late. But hey: it could be really cool, not that Xen has to have weather or anything…
Alien rain… if only I could believe a modern game engine were capable of rendering an addition so pleasant.
Makes sense, using the same form as words like partly.
Hahaha win, it got approved!