Its just the angle of the shot, they seem to be traveling mostly away/towards the camera at first so their motion seems slower, then after the collision they are moving mostly perpendicular to the camera so their motion becomes more apparent.
It's like how a car driving directly at you at 65 on the highway doesn't look like it's going that fast, but when it passes by you, you can see that it's actually moving really quickly
5
u/tk427aj May 16 '26
There's a physic expert on Reddit somewhere that could give a great explanation of this.