Can I play ripped movies on my iPad?

Your terminology is confusing. Downloading is something you do from one computer to another, copying data from a remote location. Ripping is something you do to copy data from optical media to a computer.

Ripping pretty much all commercial DVDs is illegal in the USA and many other countries. We can't help you with that, as per the Terms Of Use of this web site.

You can sync any video media in compatible format to an idevice.

Any movie in an iTunes library can be streamed to an iOS device via Home Sharing, if the iOS device is on the same local network (i.e., not connected through the cellular network), and the Mac with the iTunes library has iTunes running and Home Sharing enabled.