Possessive "Whose"

Many people have problems using who´s and whose.They sound the same but they do not mean the same. See the examples:

"Whose car is this?" or "Whose is this car?" = ¿De quién es este coche?
"Who´s that man"? = ¿Quién es ese hombre?

A couple of videos to get used to "whose":

Watch just the first nine minutes of both:

http://www.rtve.es/alacarta/videos/tve-english/tve-english-capitulo-72/2350217/
http://www.rtve.es/alacarta/videos/tve-english/tve-english-capitulo-73/2353988/