Physics of Steelpushing and Ironpulling

[The Subsumer]

Generally speaking, when you Steelpush or Ironpull, you're push/pulling on the center of mass of the object. My question is if the inverse is true as well- when an Allomancer Steelpushes, does the push come from their center of mass?

I've looked it up on the coppermind, and it says that the push originates from the user's "Center of Self", which seems to imply that that's the case, but it also says that that has ties to the user's Cognitive and Spiritual aspects, which basically means it could be anywhere. 

The reason this has been on my mind is the instances of Allomancers pulling coins into their hand from the ground or grabbing a tool from across the room, which would imply some control over where the objects are pulled to. If a coin is below your hand but above your chest when you pull on it, does it go to your hand? Your chest? Do you decide?

[Returned]

The way it's described in the books is that pushing and pulling is relative to your center of mass (often represented by the blue lines extending from metal objects to the Allomancer's chest). Observed effects match this pretty well. Most of the time when you see a cool move, like pulling a coin into your hand, the Allomancer is just pulling the object towards themselves and then moving their body to suit. Sort of like kicking something up from the ground and then grabbing it out of the air-- it's not quite that you kicked it into your own hand, but kicked it into a position from which you could catch it. Other situations seem to involve motion, like pulling something towards yourself while your body is moving through space, creating more of an arcing motion than a straight line.

It does get more complex, though it seems to take some serious Allomantic skill to do it. We see Kelsier pushing and pulling just on specific parts of metal rods to cause them to spin around or move more in "nudges" than solid pushes and pulls. We also see Wax pushing on a single bullet, then recognizing that the bullet is made of multiple pieces, and then realizing that he can push on just a specific piece. Kelsier's tricks especially suggest that there are a lot of things that a skilled Allomancer can do with careful pushes, pulls, and leverage.

[Quantus]

10 hours ago, The Subsumer said:

Generally speaking, when you Steelpush or Ironpull, you're push/pulling on the center of mass of the object. My question is if the inverse is true as well- when an Allomancer Steelpushes, does the push come from their center of mass?

I've looked it up on the coppermind, and it says that the push originates from the user's "Center of Self", which seems to imply that that's the case, but it also says that that has ties to the user's Cognitive and Spiritual aspects, which basically means it could be anywhere. 

The reason this has been on my mind is the instances of Allomancers pulling coins into their hand from the ground or grabbing a tool from across the room, which would imply some control over where the objects are pulled to. If a coin is below your hand but above your chest when you pull on it, does it go to your hand? Your chest? Do you decide?

For both Steel and Iron they will push and pull where the lines appear, which for all but the most skilled (and/or cognitively expanded perhaps?) will appear at the center of mass of the metal object.  In most of the cases mentioned I suspect it's flying toward their center and they just catch it along that path, rather than literally pulling toward the Hands.  That is possible per WOB but it's not common or easy, and for Lurchers especially it would open up a lot of strange Ripping-Apart questions.  

[Fullborn IRL]

I have an idea about aluminium feruchemy combined with steelpushing or ironpulling. The excess Identity could travel to metals pushed by the steelpusher and bounce off of them to whatever the coinshot focuses on (because pushed objects bounce) so the coinshot can allomantically push that object. And lurchers could pull objects in the way of an iron line as they focus on it. And by focusing on two or more anchors the coinshot or lurcher can make lines between them that act as a barrier for coinshots or a field that shreds and pulls things apart for lurchers.