#1
I have been messing with some movable scales lately and I had a question. If I am playing a scale in G for example, would the first note I hit have to be the root?Or is the last note I have to hit would have to be the root? Because I'm curious if the root would have to be hit at a specific time or maybe doesn't have to be hit in order to play the scale right. Also if someone could, give me a popular song with a solo and tell me what scale and what key the scale in, i thibnk that would help alot to get me more situated with scales. Maybe some Queens of the stone age songs and what scales they use in songs. Thanks alot.
#2
The first note is usually the root when learning scales just so you have a reference point, root note , tonic.

In real life music you can start and end a phrase on any note in your scale, however some notes will sound more "correct" or "predictable" depending on what you want to hear.
#3
Studying the scale shape doesn't really require starting on the root note.

Nevertheless, you will understand scales better if you know which note is the root note. Some go as far as to think the numbers 1-7 while practicing the scale in order to fix the pattern in memory. This will make it easier to make the leap from studying Major scales to the variants based on major scales (pentatonic scales, etc.).

Starting the practice of a scale from different points within the scale forms the basis of the "modes" of a scale. For example, starting a major scale on the 6th note of a scale will give you the harmonic minor scale that is related to the major scale. For example, playing the scale of C Major, but playing from #6 to #6 (or in regular musicianspeak, from A to A, since A is the sixth note of a C Major scale) will give you the scale of A minor.

Hope this helps -- good luck with your practice!