[crazydoggers]

Acceleration is a vector. So if you apply the “deceleration” long enough you’ll eventually be accelerating in the opposite direction. Without a frame of reference it’s all the same. Even with a frame of reference you’re still accelerating just that it’s in he opposite direction of the current velocity.

[Eduard]

I fly through trams in completely different directions depending on whether it accelerates or decelerates. So for sure a system's design must consider more than just the magnitude of acceleration.

[agurk]

When you go around a tight corner and are thrown to one side, what term would you use for the tram's change in motion then?

Deceleration is a useful but non-technical term, like vegetable. A tomato is a fruit which is a tightly defined concept, but it is in this loose category of things called vegetables. It's still useful to be able to call it a vegetable.

From a physics perspective all changes in motion (direction and magnitude) are acceleration, and it's correct to say the designers had to consider acceleration in most (all?) directions when designing the tram. This is including gravity's, as they tend to give you seats to sit on, rather than velcro panels and straps like on space ships.

It is useful to say to your friend in the pub that you got thrown out of your seat due to the tram's heavy deceleration, rather than give a precise vector.

[crazydoggers]

Without looking out the window how would you tell the difference between acceleration or deceleration? You can’t.

And if you say “well one way I fly to the back of the tram and the other the front” You’re arbitrarily associating “front” with decelerate and “back” with accelerate.

300gs is 300gs regardless of the direction vector of the component.

> So for sure a system's design must consider more than just the magnitude of acceleration.

What else would you need to consider? Acceleration up? Down? Left? 20%x,30%y,40%z? There’s an infinite number of directions.

[anyfoo]

Well to be fair, the person you reply to has a point. There’s a continuous range of directions, but even though I’m no spaceship engineer, I suspect they’re probably engineered to withstand acceleration better in some directions than others, given that pretty much only their thrust method, as well as gravity at source and destination, will actually be able to apply any acceleration.

[saagarjha]

You can tell because they typically accelerate faster than they decelerate.

[ryandrake]

“The enemy's gate is down.”

[FredPret]

They tend to do this with spacecraft by turning the whole craft so acceleration always comes through the floor