What does Rasengan actually do?

[rolanmts]

nothing..chidori however is instant kill my friend

LOL.
Do you remember the Fight between Naruto against Sasuke on the top of Hospital?? that time Kakashi threw them into water tank and I wont compare Chidori with Rasengan if I were you dude.

 

[Paintry4]

Rasengan is the accumulation and compact version of chakra that rotates in a variant motion and grinds everything that comes in contact of it. It just grinds in accordance of its motion.

 

[PrimeOfTheSixPaths]

It also has to deal with how much force the recipient of rasengan can push back. For example, you can punch a piece of paper youre holding and you wont see much physical damage on the paper, and it wont feel like youre punching anything. On the other hand, if you punch a piece of wood, you can feel the wood push back, and probably see damage (if you punched hard enough.)

So immovable objects, like the tree and water tank from part 1, will receive all of the blow showing the bulk of the damage as well. Compared to something that can be moved and cant apply the same amount of force as Rasengan inflicts, which is the people flying about.

At least that's what I think, along with f'ckin up the insides of them with the rotation.

 

[Darth Wignus]

It can do anything. I guess its based on output.