what is the different in erotic and nude in art?

A government grant.

Extending on the first answer:

Erotic doesn't even need a person in the picture. You can just give the idea of a person or convey sexuality mearly with the use of flowing lines. An abstract piece can be considered very erotic.

Nude, is just a person naked. Deals more with the beauty of the human body as a figure. I've never been a fan of nudes myself.

Nude is just naked. Erotic usually has a sexual aspect to it.

because any body can do nude but if some one can do art with it he a angel

whether the viewer is clothed or not and in public or not.

erotic makes your sexual senses well...ya know.
but nude can be just a nude fat old woman which makes you go ewwwwwwwwwwwwwwwwwww