Here's how to determine it:
* Stress Pattern: English words typically have one stressed syllable. In "travel," the stress falls on the second syllable, "vel."
* Phonetic Transcription: The phonetic transcription of "travel" is /ˈtrævəl/. The symbol "ˈ" indicates the stressed syllable.
* Natural Pronunciation: If you say "travel" out loud, you'll notice that "vel" is pronounced with more emphasis than "tra."
Therefore, "tra" is the unstressed syllable in "travel."