🔍 Key Concepts

• Wave dispersion – longer-period swells move faster and travel farther than locally generated wind waves • Relationship between wave period and speed in deep water (longer period = higher speed) • Typical forward speed of a typhoon/hurricane system compared to the swells it generates

💭 Think About

• Think about how fast large ocean swells can cross ocean basins and how that compares to normal ship speeds • Consider which of the options is a realistic deep‑water swell speed for long‑period waves from a strong storm • Ask yourself: could swells from a distant typhoon reach a coast many hundreds of miles away in a day or two at this speed?

✅ Before You Answer

• Eliminate any speeds that are slower than many commercial vessels, since swells can outrun the storm system • Eliminate speeds that seem unrealistically high for water waves in deep ocean • Remember that typhoon swells are long‑period waves, which travel faster than short, choppy wind waves