Generally, when is it justified to play a string of notes and only use one down or up bow?
Example: Say the music wants you to play, b (quarter note),c (quarter note), and d(half note) to be played as a phase . Would I play those 3 notes using one bow action? How do I choose what notes get a full bow and what string of notes get a full bow?

Many times the musical notation will indicate the bowing technique to be used. A small "v" or up-bow, over the note will indicate that a note should be played by drawing the bow from the tip to the frog by moving the bow toward the body. In oppostion is the down-bow, indicated by a small bracket over the note, in which one draws the bow from the frog towards the tip moving away from the body. These marking may be followed by a slur marking (rainbow shape) above the notes to be played in this manner. Another indicator would be a legato notation in the music.

Thank you ShanaMaria for you the bowing information. It does help. Us violin players have to stuck together.

sorry not a violin player...viola, mandolin, piano. mostly piano really. I have a lot of respect for violinists though, they are always forced to play the hard uncool parts, and appear to be oblivious to the fact!

Well, we are in the same family, the string family. We are both musicians. Let me say, us strings players need to stick together.

I'm believing that more and more.I just don't understand some of the wind and brass members. Some are very nice. Others are just very odd...

One of the differences is that they have to concentrate on producing a note using wind from their body. But we simply play, and do not have to worry an omberture.