I digitized the TPM Force-speed sequence, did an inverse-telecine with VirtualDub to convert back to the original theatrical frame rate, and dumped to image sequence.
![Image](http://www.stardestroyer.net/BoardPics/StarWars/ForceSpeed-0.jpg)
Time: 0 seconds. This is before they start.
![Image](http://www.stardestroyer.net/BoardPics/StarWars/ForceSpeed-1.jpg)
Time: 0.04 seconds. They initiate Force-speed. Notice how they've become transclucent. You can actually see the door right through Qui-Gon.
![Image](http://www.stardestroyer.net/BoardPics/StarWars/ForceSpeed-2.jpg)
Time: 0.08 seconds. It's hard to see because they're translucent in Force-speed, but judging by Obi-Wan's saber, he's covered roughly 1 metre. To accelerate from standing start to cover 1 metre in 0.04 seconds requires acceleration of 1250 m/s^2, or more than one hundred fucking G's at a minimum. Even if the location of his sabre is misleading and he only covered 1/2 metre in that time, he would still need to accelerate at more than 60 G's.
![Image](http://www.stardestroyer.net/BoardPics/StarWars/ForceSpeed-3.jpg)
Time: 0.12 seconds. Obi-Wan has covered another metre, which indicates that he's topped out at around 20-30 m/s (45-68 mph). That's fucking automobile highway speed, pal. And we're not just talking about moving his arm or bending his hips; we're talking about accelerating his entire body.
![Image](http://www.stardestroyer.net/BoardPics/StarWars/ForceSpeed-5.jpg)
Time: 0.21 seconds. Notice how Qui-Gon is quite obviously transclucent in this scene; he is only visible as a shadow. Obi-Wan is almost completely invisible; if it weren't for his sabre, you wouldn't even know he's there. Now we know the ANH novelization wasn't exaggerating when it said he could become wraith-like.
I think that after AOTC, people have forgotten how formidable the Jedi were in TPM, at the height of their power before the shroud of the Dark Side fell upon them.