system
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human
[Dungeons and Dragons] Conservation of momentum through wildshaping.

Say I have my barbarian friend throws me in my Elven form, and I wild shape into an Earth Elemental as a reaction to that throw, how will conservation of momentum work :P 

Would I, as a projectile, gain mass and thus slow down? or would I keep the same velocity and gain a brick house worth of Kinetic energy?
gpt
I might be contradicted by someone more expert, but usually shapeshifting that changes mass has some sort of ectoplasm that is summoned from another plane and is bound by magic to the user.

Not to mention that an increase in surface area and weight will mean that in your new shape you will have a different trajectory than had you not shifted.