"Thrown weapon" in CRB says
Thrown Weapons: Daggers, clubs, shortspears, spears, darts, javelins, throwing axes, light hammers, tridents, shuriken, and nets are thrown weapons. The wielder applies his Strength modifier to damage dealt by thrown weapons (except for splash weapons). It is possible to throw a weapon that isn't designed to be thrown (that is, a melee weapon that doesn't have a numeric entry in the Range column on Table: Weapons), and a character who does so takes a –4 penalty on the attack roll. Throwing a light or one-handed weapon is a standard action, while throwing a two-handed weapon is a full-round action. Regardless of the type of weapon, such an attack scores a threat only on a natural roll of 20 and deals double damage on a critical hit. Such a weapon has a range increment of 10 feet.
The first question is: "Such a weapon" means ALL thrown weapons or a weapon that isn't DESIGNED to be thrown.
The second question is:
When a ALCHEMIST use Strafe Bomb, it has 40 range increment or it just can hit 40 range?The third question is about monster Sandman.
Sandman is a monster in Bestiary 2.
it has Defensive Abilities amorphous; DR 10/bludgeoning; Immune elemental traits.
but elemental traits are include
"Not subject to critical hits or flanking. Does not take additional damage from precision-based attacks, such as sneak attack."
Then the amorphous is just a joke?, it is include amorphous.
1) Weapons that do not have a range entry on the weapon table have a range of 10'. If it has a range entry you use that range.
2)
strafe bomb
Strafe Bomb (Su): The alchemist can throw bombs that splash in a 40-foot line rather than affecting a radius. The line starts at the alchemist and extends away from him in the direction he chooses. The alchemist designates one creature in the squares affected by the line to be the target of the bomb and makes his attack roll against that creature; all other squares in the line take splash damage. If the alchemist has the explosive bomb discovery and throws an explosive strafe bomb, the line of splash damage is 80 feet long instead of 40 feet.
Strafe has effectively zero range. It is a 40 line of splash damage starting at a square adjacent to you. One target in that 40' line gets attacked.
3) Effects maybe superfluous sometimes, but you never know when it might one day be relevant. If there isn't already it isn't hard to imagine an effect or class ability similar to a golembane scarab that would bypass elemental immunity, and the sandman would still be amorphous.