“Are you free now?” / “What's up?”
Here free means available, rather than having freedom. Are you free now? asks whether someone has time. What's up? can be a greeting, but here it asks what the caller wants or what has happened.
A1-34 / CEFR A1 / EPISODE 34
Inviting a friend to study by phone
SceneFrank phones Tina.

WORDS & CONTEXT
Here free means available, rather than having freedom. Are you free now? asks whether someone has time. What's up? can be a greeting, but here it asks what the caller wants or what has happened.