On December 26, 2004, a great earthquake occurred off the coast of Sumatra and triggered immense waves (tsunami) that killed some 200000 people. Satellites observing these waves from space measured 800 kmkm from one wave crest to the next and a period between waves of 1.0 hour. Part A What was the speed of these waves in m/sm/s

The speed of these waves is 222.22 m/s

Explanation:

A.

Since, we know that the speed of a wave is given by the formula:

v = fλ

where,

v = speed of wave

f = frequency of wave

λ = wavelength

Here,

λ = distance between consecutive wave crests

λ = 800 km = 8 x 10⁵ m

f = 1/Time Period = (1/1 hr) (1 hr/3600 s)

f = 2.77 x 10⁻⁴ s⁻¹

Therefore,

v = (2.77 x 10⁻⁴ s⁻¹) (8 x 10⁵ m)

v = 222.22 m/s

Given that,

200,000 people where killed due to earth quake in December 2004

Satellite observing measure a wavelength of 800km crest to crest

Crest to crest implies one wavelength

λ = 800km = 800,000m

Period of One hour

T = 1 hour = 3600s

Then, we want to find speed of wave.

Using wave equation

v = fλ

Where

f is frequency in Hz

v is speed of wave in m/s

λ is wavelength in m

Where f = 1 / T

Then, v = λ / T

v = 800,000 / 3600

v = 222.22 m/s

Then, the speed of the wave is 222.22 m/s