Intro to Oceanography Homework 8

If the wave height is doubled, the total energy in the wave will increase by a factor of

4.

Waves can be created by: - winds. - gravitational attraction of the moon. - the impact of large objects on the water. - earthquakes. - density gradients. - A, B, C, and D but not E - A, C, and D but not B or E - A and D but not B, C, and E

A, B, C, and D but not E

The location of rip currents can sometimes be determined by looking for: - narrow zones of increased turbidity in the water. - floating debris in the water moving offshore. - a narrow zone of decreased wave heights in the surf zone. - A, B, and C - A and C

A, B, and C

The maximum height of the waves that can potentially be created by a specific storm depends on: - wind speed. - wind duration. - fetch. - A, B, and C - A and C but not B

A, B, and C

Waves form several different types of breakers depending on the: - wave height. - wave period. - slope of the seafloor. - the grain size of the sand on the beach. - A, B, and C

A, B, and C

Waves: - transport sand and sediment along the coast. - provide opportunities for recreation. - erode coastlines and beaches. - A, B, and C - B and C

A, B, and C

Refer to figure 7. At which location would the wave height be greatest?

B

Tsunamis can be created when: - tidal forces are at a maximum. - earthquakes cause vertical displacement of the seafloor. - unusually strong storms combine with high tides. - strong surface currents meet each other. - volcanoes erupt under or at the ocean surface. - B and E

B and E

Refer to figure 7. At which location would the energy of one meter length of wave crest be the least?

C

Deep water waves of wavelength "L" are waves that travel in water with a depth greater than

L/2.

Waves of wavelength L that travel in water depths less than _____ are called shallow water waves.

L/20

Capillary waves have V-shaped crests and rounded troughs.

False

The restoring force for capillary waves is the Coriolis effect

False

Wave energy is usually dissipated rapidly in the open ocean.

False

A tsunami can travel almost as fast as a jet airliner.

True

A tsunami is always a shallow water wave.

True

Wave refraction bends waves to make them align more parallel with the shore.

True

The total energy possessed by a wave is primarily a function of

height.

Dispersion of waves

increases with increasing distance from a storm.

Capillary waves aid in the formation of larger waves by

increasing the roughness of the sea surface.

The point in a standing wave where the water surface does not change elevation is called

node

Wave refraction tends to concentrate the energy of waves

on headlands that extend out into the water.

Waves become unstable and break when their wave height exceeds approximately

one seventh of the wavelength.

As a wave moves into shallow water, its _____ does not change.

period

The time it takes a wave to travel the distance equivalent to one wavelength is the wave

period

A wave that moves freely over the water surface is called a

progressive wave.

Internal waves can occur along sharp density gradients in the ocean called

pycnoclines.

The return flow of water off the beach can be concentrated in narrow zones called

rip currents.

Capillary waves are created by

small variations in wind speed and pressure that occur as the wind blows over smooth water.

Internal waves typically have heights that are far greater than surface waves because

the density difference across the boundary that they flow on is much smaller than the density difference between air and water.

As a wave moves from deep water into shallow water the orbit of a water particle changes from a circular orbit to a more elliptical orbit. The reason for this change in orbit is

the wave motion touches the seafloor where some energy is lost by friction and this flattens the orbit.

Waves are usually refracted when they approach the shoreline because

they approach at an angle and one end of the wave enters shallower water first.

When two wave trains meet

they pass through each other and emerge unchanged.

The lowest elevation of the wave is called the wave

trough

The velocity of shallow water waves is a function of

water depth.

The relationship between wave height and wave amplitude is that

wave amplitude is half of the wave height.

The speed of a wave is equal to

wavelength divided by period.

Wave dispersion is caused by

waves of different wavelengths moving at different speeds.

The steepness of a wave can increase

where it travels in a direction opposite that of a strong surface current.

As a wave moves from deep water into shallow water the wave height

first decreases then increases.

Rip currents often flow off the beach where

a depression or shallow channel runs offshore from the beach.

Breaking waves some distance from shore often are evidence of

areas of slightly shallower water.

Reefs and sand bars can help protect beaches from erosion by

dissipating some of the energy in the waves by making them break offshore.

The group speed of a wave train is _____ speed of the individual waves.

equal to one half of the