Short Clip of Prey Capture
How the jaws are used
When a prey animal falls into the antlions pit, the antlion senses it through vibration and will snap its jaws closed around the prey animal, and inject venom into it to disable the preys ability to flee. In order to inject the venom the jaws of the antlion must puncture the out carapace of the prey animal.
If the prey animal manages to dodge the initial bite, the antlion also uses it's jaws to throw sand onto it, knocking it down into the middle of the pit for another attempt.
Physics of the Jaws
The jaws of the antlion create potential energy by opening their jaws to near 180 degrees. When they go for the bite, the jaws have enough pressure to pierce through the out carpace of its prey. Unfortuantely I could not find any info for how much pressure the antlion has in its jaws.
The physics of throwing sand are pretty basic, so there will not be a lot of info here. The antlion flings it's jaws into the sand and then up and out, causing sand to fly into the air only after gravity was overcome with kinetic energy. After it reaches the apex of its descent, the force of gravity cause the sand to fall back into the pit and into the animal running away.