A 2-d emotion wheel is a way of categorizing emotions based on their action-tendencies (rest/movement) and their valences (pleasant/unpleasant).
Music tends to express emotions by imitating our actions and behaviors when we’re experiencing emotions.

For example, we “jump for joy”: we tend to be physically active when we experience joy. On the opposite quadrant, we can be “down in the dumps”: we are physically down (lying down) and tend not to move as much when we’re sad.
To dig into how music expresses emotions like this, check out the Music and Emotion Course: