Yes, under US copyright laws, creative works of authorship by officers or employees of the federal government have no copyright, making them public domain.
However, not everything published by the US government was created by the federal government and other authors or publishers may retain copyright ownership. For example, an author could license the US to publish something or the US could contract to have some work created, where the independent contractor owns the copyright.
Works for which protection has expired are in the public domain. In the US, works of the federal government are not protected.
Under US copyright law, there are no recordings that are public domain; they are either covered under state copyright law prior to 1972, under federal copyright law if published after that, and under federal copyright law if they were never published at all. The only possible public domain records would be some that were published before 1989 and after 1972 without the necessary copyright notice or registration.
Yes; in the US, materials published prior to 1923 are in the public domain.
Yes.
An extensive list of songs in the public domain (in the US) is linked below. It's much harder to find public domain recordings, as the copyrights for sound recordings are especially convoluted.
Yes; US works prior to 1923 are in the public domain.
Materials can enter the public domain when copyright term expires, protection is not renewed (renewals are not available for new works), the creator donates the work to the public domain, or the materials are a work of the US Government.
No, and it is staunchly protected by its rightsholders, as licensing it brings in about $2 million annually. In the EU, it will enter the public domain in 2017; in the US it will be protected through 2029.
It is protected in France and other countries with a copyright term of life plus 70 years (such as the US), but in the public domain in shorter-term countries such as Canada.
Yes; Robert W. Service's works entered the public domain in Canada (and other countries that acknowledge the "rule of the shorter term") in 2009. Just to be contrary, that particular poem entered the public domain in the US in 2003.
Nothing as all such photos were taken by agencies of the US Federal government, making them in the public domain (unless still classified).
In most countries, new works are entering the public domain every year on January 1. In the US, no new works will enter the public domain until 2019.