Is an exclamation point the proper punctuation for this sentence you like to hit ball?

No, an exclamation point is not the proper punctuation for the sentence "you like to hit ball".

Here's why:

* It's not a statement of strong emotion: The sentence is a simple question about someone's preference.

* It lacks a subject: The sentence is missing a subject ("Do you like to hit ball?").

The correct punctuation is a question mark:

* Do you like to hit ball?

You could also add a subject to make it a statement:

* You like to hit ball.