[jQuery] the best way to handle a group of div elements

Hi folk,

In HTML code I have this situation:

<div id="nam1" class='nc1 nc2 nc3 hidden'></div>
<div id="nam2" class='nc1 nc2 nc3 hidden'></div>

I would like to remove "hidden" to class value which class value
starts with "nc1"

I tried the following jquery code, but it doesn't work.

$(.nc1).removeClass('hidden')

Any ideas?

thanks

Antonio