In Keyword Design, I use a single word as inspiration for a mundane item, a magic item, a feat, a spell, and a class option. Today’s word is “KINEMATICS” as suggested by Bastille.

Bastille didn’t give me an easy one, but kinematics certainly has interesting potential. “The branch of mechanics concerned with the motion of objects without reference to the forces that cause the motion.” I’m going to occasionally reference the forces that cause the motion, but I appreciate the freedom of not being forced to.

“Kinematics”
TYPE	NAME	DESCRIPTION
Mundane Item	Kinetic Cradle	A device that uses kinetic energy to create a rhythmic sound that facilitates concentrated work.
Magic Item	Bead of Back Blasting	This tiny, bull-like bead knocks foes back.
Feat	Power Through	Bull rush objects to break them.
Spell	Telekinetic Domination	Dominated a target physically.
Class Option	Force Slayer	A telekinetic warrior who forges weapons from the energy they control.

New Mundane Items
KINETIC CRADLE
Cost: 1200 gp Weight: 1 lb
Once one suspended metal ball in this lineup is set in motion, the energy generated by the impact of a ball on one extreme is enough to move the ball on the opposite extreme an equal amount. Beyond a display of science in motion, the rhythmic clacking of the balls impacting one another is soothing, facilitating deep thought.
When deciphering arcane magical writing or copying a spell next to an active kinetic cradle, a character gains a +5 bonus to Spellcraft checks.
Activating a kinetic cradle is a move action that provokes attacks of opportunity.

Originally the bonus was going to be to concentration checks, but the majority of situations that call for a concentration check do not allow for the setting up of a Newton’s Cradle. Applying the bonus to Spellcraft checks, especially for copying spells, made more sense and was a benefit more in line with what I thought such an item should realistically cost.

 

New Magic Item
BEAD OF BACK BLASTING
Aura moderate transmutation; CL 10th
Slot none; Price 1500 gp; Weight –
DESCRIPTION
This gnarly black stone is roughly spherical save for two pointed protrusions jutting out like the horns of a taurus. When activated, a telekinetic force pushes nearby creatures backwards. When the bead attempts to bull rush a target, it uses its caster level in place of a base attack bonus and has an effective Strength of 20, giving it a Combat Maneuver Bonus of +15.
There are two ways to activate a bead of back blasting:
Targeted: The target of a successful touch attack, the force of the exploding bead is subject to a bull rush attempt. This can be done as a standard action or an immediate action. Activating the bead as an immediate action expends the bead.
Area: When thrown as a grenade weapon, all adjacent creatures are subject to a bull rush attempt. Using the bead of back blasting in this way expends the bead.
CONSTRUCTION
Requirements Craft Wondrous Item, bull’s strength, telekinesis; Cost 750 gp

Another GI Joe reference, probably my most obscure!
I rarely buy expendable items other than healing potions. I also rarely build characters whose abilities have limited uses per day. I’m saying 4e was never for me, OK?
No, what I’m saying is that even though the visual that inspired this idea -knocking back an attacker before they can attack- I can see myself only using the non-expendable version. Or buying it with the intent to use it defensively and just not.

New Feat
POWER THROUGH (Combat)
You use your momentum to break barriers.
Prerequisites: Str 13, Improved Bull Rush, Power Attack, base attack bonus +1.

Benefit: You can break unattended objects of at least your size with a bull rush combat maneuver. If the result of your combat maneuver roll is equal to the target object’s break DC, the object gains the broken condition. If you break the DC by 5 or more, you may move an additional 5 feet per 5 by which your roll beats the DC, up to your total movement for this round. 

Super situational, but thanks to the brawler, situational combat feats actually get used!
For the record, I wanted to find an image from The Princess Bride of when Fezzik knocked a door down, allowing Inigo Montoya to continue pursuing the six-fingered man. Google wasn’t helpful. So I just Googled “break door down” and… voilà? 

New Spell
TELEKINETIC DOMINATION
School transmutation; Level sorcerer/wizard 4;
Casting Time 1 standard action
Components V, S
EFFECT
Range medium (100 ft. + 10 ft./2 levels)
Target one creature
Duration concentration
Saving Throw Fortitude partial, see text; Spell Resistance yes
DESCRIPTION
You surround the target’s body with a rigid force field that you control. As long as you spend a standard action to concentrate on the spell, you can choose to affect the target in one of the following ways:

• Paralyze your target, as hold monster. The target may attempt a saving throw as a full round action that does not provoke attacks of opportunities, ending the spell with a successful save;
• Reducing the target’s mobility, as slow. The target may attempt a saving throw as a free action, acting normally on their turn with a successful save. They remain under the effect of the spell as long as you concentrate;
• Force the target’s hand, controlling their body similar to dominate person. The target may attempt a saving throw as a free action, ending the spell with a successful save.
• Crush them slightly, dealing 1d6 bludgeoning damage, +1/caster level. A successful save halves the damage.
• Hamper them, as entangle. They do not get a save to resist this effect.

It’s a Swiss army spell, but one that covers some basic functions of telekinesis as it’s depicted in pop culture but that aren’t covered by the telekinesis spell. It’s not that creative but it’s functional, and that’s all I need sometimes.

New Class Option
KINETIC WARRIOR (slayer archetype)
A crafty combatant who conjures weapons of pure energy.
Weapon and Armor Proficiency: A kinetic warrior is proficient with all
simple weapons.
This alters the slayer proficiencies.
Elemental Focus (Su): At 1st level, a kinetic warrior chooses one element from the kineticist class list of elements on which to focus. This element determines how he accesses the raw power of the Ethereal Plane, and grants him access to specific wild talents and additional class skills. He gains his selected element’s basic utility wild talent (basic telekinesis, basic aerokinesis, etc.) as a bonus wild talent. Unlike a kineticist, a kinetic warrior only ever gains one element. If the chosen element grants a class skill already on the slayer class skill list, the kinetic warrior gains a +2 bonus on checks with that skill. Otherwise this functions like the kineticist class feature of the same name.
Kinetic Weapons (Su): A kinetic warrior can generate energy to form kinetic weapons. This weapon can take the form of any melee weapon with which the slayer is proficient. A kinetic weapons uses the statistics of the weapon it resembles, except that the damage it is energy damage based on the kinetic warrior’s elemental focus. He can generate one kinetic weapon as a swift action or two kinetic weapons as a move action. If a kinetic weapon ever leaves the kinetic warrior’s hands, it immediately disappears.
A kinetic warrior’s kinetic weapons gain a +1 enhancement bonus at 5th level. This enhancement bonus increases by +1 every 5 levels thereafter, to a maximum of +4 at 20th level.
This ability replaces studied target.
Kinetic Blast (Sp): A kinetic warrior can unleash a blast at a single target that deals an amount of energy damage equal to 1d6 + the kinetic warrior’s Constitution modifier, increasing by 1d6 at 3rd level and every 3 levels thereafter. The energy type is based on the kinetic warrior’s elemental focus. This otherwise functions as a kineticist’s kinetic blast ability.
This ability replaces track and sneak attack.
Utility Wild Talent: At 4th level and whenever the kinetic warrior gains a slayer talent, he can instead choose a utility wild talent of the element in which he chose to focus. The kinetic warrior’s effective kineticist is equal to his slayer level for the purposes of qualifying for utility wild talents. Unless otherwise noted, the DC for a saving throw against a wild talent is equal to 10 + the wild talent’s effective spell level + the kinetic warrior’s Constitution modifier. A kinetic warrior can never have more wild talents than slayer talents (not counting the basic utility wild talent gained at 1st level).
This ability alters slayer talent.
Metakinesis (Su): At 7th level, a kinetic warrior gains the ability to alter his kinetic blasts as if with metamagic feats by accepting burn. By accepting 1 point of burn, he can empower his kinetic blast (as if using Empower Spell). Additionally, he can accept 1 point of burn to change the energy type of his kinetic weapons to untyped damage for 1 minute.
At 14th level, by accepting 2 points of burn, he can maximize his kinetic blast as if using Maximize Spell. Additionally, he can accept 2 points of burn to deal an extra 1d6 points of energy damage (based on his elemental focus) on a successful hit for 1 minute, or give his kinetic weapon one of the following weapon properties for 1 minute: dancing, keen, speed, or vorpal.
At 19th level, by accepting 3 points of burn, he can quicken his kinetic blast as if using Quicken Spell. Additionally, he can accept 3 points of burn to deal an extra 3d6 points of energy damage (based on his elemental focus) on a successful hit and an extra 1d10 points of energy damage on a successful critical hit (or an extra 2d10 points of energy damage if the weapon’s critical multiplier is x3, or an extra 3d10 points of energy damage if the weapon’s critical multiplier is x4) for 1 minute, or give his kinetic weapon two of the above weapon properties for 1 minute.
At 20th level, by accepting 4 points of burn, the kinetic warrior can use his kinetic blast twice with the same standard action, or swift action if he also uses metakinesis to quicken the blast. When she uses a double kinetic blast, all modifications, such as metakinesis, apply to both of the blasts, but the kinetic warrior needs to pay the burn cost only once. Additionally, his kinetic weapons permanently deal an extra 3d6 points of energy damage (based on his elemental focus) on a successful hit and an extra 1d10 points of energy damage on a successful critical hit (or an extra 2d10 points of energy damage if the weapon’s critical multiplier is x3, or an extra 3d10 points of energy damage if the weapon’s critical multiplier is x4).
This ability replaces stalker, quarry, improved quarry, and master slayer.

Two notes about this archetype:
First, this is a slayer archetype that replaces most slayer class feature. At one point it replaced all but one, but then gave one back. It also changes the class’ proficiencies. The only legacy of the slayer class is the skills, and I kind of feel like 6 + Int is too much. So is this even a slayer anymore?
What I discovered about the slayer is that most of the class features are tied to studied target. This makes sense, it’s the class’ main feature, but I can’t think of another class with so many abilities tied to its main feature. Changing one necessitated changing most. The other main feature of the slayer is sneak attack, which is easier to swap out, and is swapped out by a comparable ability, damage-wise.

Technicalities aside, I functionally like this “slayer” archetype. It’s a martial kineticist that plays like an elemental bloodrager while not being especially complicated. Staring technicalities in the face, this might be the simplest new base class or hybrid class I ever designed.

Second, if the keyword is kinematics, why didn’t I just make this a Jedi-esq telekinetic warrior? While that is common practice, I don’t like narrowing the availability of an option down to fit a product. Between the Advanced Race Guide and the Advanced Class Guide, there are in the neighbourhood of 100 feats that give a generic enough bonus they could apply to many builds, but those builds are blocked by unnecessary prerequisites. The game rarely takes an option that’s more specific than it needs to be and reuses those mechanics more broadly (the swashbuckler turning the gunslinger into the melee weapon slinger being one of the only examples). So this could have been the telekinetic warrior, but instead it’s the telekinetic warrior plus any other element that is or will ever be available for the kinetisist in about the same word count.

 

Thanks again to Bastille for the keyword suggestion. If you have thoughts on the balance and use of these abilities, or you would like to offer a single word that you think can inspire a mundane item, a magic item, a feat, a spell, and a class option, let me know in the comments below.