The word, 'tore' would refer to an excited tone. A tone is the voice of the author which shows how they the atmosphere around the characters are. Its like the mood of the sentence.
When you get a present and if you're excited about it, you will quickly tear the gift wrapping to see what the present it. If you're not excited, you might just take off the gift wrap carefully.
"A. childrens'" is the proper answer because the musem belongs to the children, which is plural. If a single child owned the museum somehow, it would be The Child's Museum.
