Seismic waves

xkcdseismic_waves

Source: http://www.xkcd.com/723/

green line

The above comic pretty much happened when a 5.8 earthquake hit Virgina in 2011, as people up and down the East Coast received tweets about an earthquake seconds before feeling the earthquake for themselves.

It also inspires the obvious word problem for Algebra I students.

When an earthquake hits, seismic waves travel at about 5 meters per second. Suppose that Alex tweets about the earthquake 30 seconds after feeling its seismic waves. The tweet travels at about 200,000,000 meters per second. How far away does someone have to be from Alex to receive the tweet before also feeling the seismic waves?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.