In this form را, it's just used in written Farsi. It changes a little in colloquial Farsi. In some places it's " رو ro " and in some it's " و o ". In some situations, using رو sounds a little unnatural. but there are situations in which, the رو form should be used to be natural. I'll try to explain it through examples below: " اون دو تا کتاب رو با خودت ببر = oon do ta ketab ro ba khodet bebar " --> a little literary! " اون دوتا کتابو با خودت ببر = oon dota ketabo ba khodet bebar " --> it's more commonly used. " من اون دوتا رو با خودم بردم = man oon do ta ro ba khodam bordam " But it can't be " man oon dota O ba khodam ordam ". No way! And one more thing, رو is more used in formal situations. There's no clear difference between these two, you just have to get used to these and while talking, see which can sound more natural. But I recommend you to use the form رو as you're a beginner. It makes perfect sense :)

yes it is. but differently. in conversational Farsi "ra" turns into "ro" or "o". if the noun if follows ends in a consonant we use "o" if it ends in a vowel we use "ro" for example "ketabam ra bede" (which is the written form for [give me my book]) will turn into "ketabam-o bede". or "bache ra didam" (I saw the child) will turn into "bache ro didam".