Self-determination theory has been particularly useful in explaining and predicting the motivations and actions of adult learners in educational setting. (Rothes, Lemos, and Goncalves, 2017). According to this theory, motivation arises from either autonomous regulation, which arises within the individual and decisions to initiate and continue engagement are made by the individual, or controlled regulation, which finds decisions motivated by other controls. Controlled regulation can be deconstructed into external regulation and introjected regulation. External regulation is controlled by anticipated rewards, but introjected regulation has been partially internalized by the learner.
For many individuals who are community college students, motivation is affected by their sense of future identify. The participate in school to earn a degree, enter a field of work, or otherwise influence who they perceive themselves to be. That goal may have originated as an internal source, but it is more characteristic of external motivation rather than an internal motivation. Students who study math because it is a requirement for their degree program are neither learning simply to earn the grade (which would be classic external motivation) nor are they learning because of a deep interest in math (which would be classic internal motivation).
Reference
Maiese, M. (2017). Transformative Learning, Enactivism, and Affectivity. Studies in Philosophy and Education, 36(2), 197–216.