Why does my Audi A5's engine make a high-pitched noise when I accelerate?

I recently noticed that whenever I accelerate in my Audi A5, there's a high-pitched noise coming from the engine. It doesn't happen when idling or at a constant speed. What could be causing this and how can I fix it?

It's possible that the noise is coming from a loose or worn out belt. You can visually inspect the belts to check for any signs of wear and tighten or replace them if necessary. If that doesn't solve the issue, it could also be a problem with the pulleys.