Per the ADSBx track the plane was at 101kts (115 mph / 185kph) just before crossing taxiway D, which would be where it hit the firetruck. It still had enough energy afterwards to reach taxiway E, 600ft away.
A plane is basically a flimsy tube. A firetruck is a solid brick comparatively. The plane out weighs the fire truck by a lot and out speeds it by a lot. So yeah, destroying the whole front of the plane to punt the truck it sounds about right for a 25 on 5 or 35 on 10/15 type rear ending to me. Flipping doesn't really sound that unreasonable considering that the plane made contact with the top of the truck (just by virtue of comparative height) and contact may not have been straight on. Even if it left the pavement on it's wheels airport firefighters aren't exactly who I'd bet on (they're middle of the pack) to keep the truck on it's wheels if they got surprise kicked off the road especially if there's an embankment involved.
An Oshkosh 1500 4x4 is 62000 lbs GVWR (wiki says kerb weight but it’s incorrect).
The plane was landing and the truck was heading to an intervention, so they were likely close to empty and to GVWR respectively.
And again, 25mph is the final ground speed, after the plane punted the truck and kept on going for 600ft.
Wouldn't final ground speed be zero?
https://pbs.twimg.com/media/HEFF17eaYAA_sgq?format=jpg
I can’t tell what’s the truck and what ’s the remains of the plane in this pic.
Another wider angle:
https://pbs.twimg.com/media/HEFDcS4bwAA8uu7?format=png&name=...
There’s no way this scene happens from a plane colliding with a truck at 24mph.
The back of a firetruck is not a working implement like a dump truck is nor is it sufficiently strong for mounting a crane or man bucket like utility bodies often are It's a bunch of sheetmetal boxes to hold stuff and cover stuff and there's a water tank back there somewhere. In the middle down low some pumps are buried. Basically don't think of it as being any more structural than a box truck body because it's not. All that stuff got shredded, obviously, since they're only really meant to bear their own weight and were subject to all the truck tossing forces here. Beyond that the truck is in pretty good shape. It's not uncommon for a good "off the highway and into the ditch" crash to rip tandems off, twist frames, etc. None of that has happened here. The plane is pretty rough, but that's expected. They are 100% tin cans. Ground equipment moving at idle speeds will absolutely shred them before the operator even feels resistance. A goose hit square on the leading edge of a small jet's wing will put a massive dent in (and apply red paint, lol).
24 sounds about right for a closing speed for plane onto truck. Whatever the baseline speed of the truck was cannot have been that high or the truck would be absolutely shredded from the barrel roll and as it stand the cab is barely pushed in.
The last recorded ground speed data of 24mph also shows a wildly different heading (going from 30deg ish to 170ish). So it probably happened after the collision and was part of its deceleration. As far as I know, the truck would have been crossing the runway so the effective speed perpendicular to the plane would be zero except for directional shear I guess.
The speed was much higher per sibling comment, but also remember that kinetic energy also involves mass (planes are heavy) and the square of the velocity.
* https://en.wikipedia.org/wiki/Kinetic_energy
The latter is why (e.g.) going 100 units/hour has twice the KE of going 70 units/hour in a car.
edit: Looking into this a bit more it looks like the plane came to a stop around crossing E while the emergency vehicle was crossing at D(based on ATC recordings). Using the following map as reference[2], the 58kts point was around E, while the previous recorded point which was just before D was 114kts.
[1] https://www.flightradar24.com/data/flights/ac8646#3ede6c39
[2] https://www.flightaware.com/resources/airport/LGA/APD/AIRPOR...
(Though some of the major damage may have happened while deplaning the passengers)
People into boats need to understand this. Even a boat that travels no more than 4mph can crush you easily. This is why you never get on to moving boat from the front. Many people have made a mistake because speed is not high.
Speed, kinetic energy and acceleration are all interrelated and at the end of the day it's all forces (to some extent) and no amount of hand wringing commentary is going to replace genuine understanding of them.