In UT there are 3 main physic tricks you can take advantage of.
One of these is the elevator jump. If you jump on an elevator, the elevator speed is added to the jump speed, so you jump much higher than usually. This is especially popular in Deck16, where you can jump up at the armor, even though the elevator is only half-way up. This is also how you can jump from the elevator to the sniper rifle in Codex, or from the main elevator in Curse to the middle bridge.
The next trick is only possible with dodging and only if there are non-vertical walls. If you dodge against such a wall your sidespeed is converted to upspeed, so you can reach higher places, than when jumping normally. Especially useful is this trick in Curse, where there are lots of non-vertical walls. You can jump up to the healthpacks/secret ammo room near the flak from amp for example. But this is also useful in Liandri for example, where you can dodge up to the Bio Rifle when coming from the flak.
The last physic trick is the Impact Hammer jump, I already mentioned. Just look down to the floor, while loading your Impact Hammer in primary fire, then jump and release the fire at the same time. You will jump much higher than usually at the cost of 54 health. You can also jump with the secondary fire. You will only lose 13h, but you won`t jump as high. This is perfect for the jump to the amp in Turbine.
This works with every weapon, that has splash damage. But the Impact hammer has the best damage/height efficiency. The only occasion where I would use a different weapon is, if you spawn at the ASMD in Turbine and try to get shield as fast as possible. The fastest method is to open the shieldroom with an ASMD primary and immediately jump up with an ASMD secondary jump.
Here is a demo of all the 3 physic tricks done in Curse.