9.13.2: Chapter Questions
- Page ID
- 50278
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)STUDY QUESTIONS
- Why do successive waves that arrive at the beach have different heights?
- You are standing at the end of a pier with a stopwatch. How would you measure the average wavelength of the waves passing by?
- What is a restoring force, and why is it necessary if waves are to develop?
- List the factors that determine the maximum wave height in a sea. How do they differ in the Atlantic and Pacific Oceans?
- Why do deep-water waves sometimes break instead of just getting bigger?
- Why is it not a good idea to enter a narrow harbor mouth when the tide is flowing out of the entrance and large waves are entering the harbor mouth from offshore?
- Why do waves disperse as they move out from a storm? What would you see if you stood at the beach and observed the waves for many hours after the first waves from a distant storm arrived on an otherwise calm sea?
- What are wave trains? Why do they move more slowly than individual waves?
- What are the principal differences between internal waves and surface waves? Why do these differences exist?
- What are rip currents, and why do they occur?
- Why do tsunamis travel almost as fast as jet aircraft? Why would you not even notice a passing tsunami if you were on a boat far out to sea in deep water?
- Describe standing waves. How do they differ from progressive waves? How do they resemble progressive waves?
CRITICAL THINKING QUESTIONS
- If the surface tension of water were much smaller than it is, how would you expect this to affect the formation of waves on the ocean? How would the waves behave differently when they approached a beach?
- You are sailing across the water into an almost regular swell that comes from directly ahead of you. Suddenly you notice that the same swell now appears to be coming at you from two slightly different directions at a small angle from each side of the boat’s bow and the wave pattern ahead looks confused compared to the smooth swell you were sailing on a few minutes before. What are you seeing, and why? Should you be concerned?
- Sailing ships exploring the oceans before there were maps were able to safely enter lagoons of atolls or those behind fringing coral reefs, even though in many such reefs there are only a few narrow entrances where the water is deep enough for safe passage. (a) How did they do this? (b) How might they have done this differently on days when the ocean surface was extremely calm, lacking even a gentle swell?
- Describe how waves would be refracted if they entered a very long basin whose underwater sides described a perfect V shape, with the depth of the V slowly decreasing with distance into the basin. Draw your answer showing the shapes of several successive waves as they travel up the basin. Include wave rays in your diagram.
- In some parts of the oceans, there are often strong seas with breaking waves. In other areas, the waves are usually smooth swells. In yet other areas, the sea surface is often calm, and finally, in some areas, ships may encounter large swell waves with steepened fronts. Using what you have learned in this chapter, identify on a map at least one area of the Pacific Ocean where you would expect to find each of these situations. Explain the reasons for your choices.
- In strong storms at sea, ships often alter course, for safety, so that they travel directly into the direction from which the wind and waves are coming, even though this may be far from their intended course of travel. Why do you think it is safer to travel into the wind and seas than at an angle across this direction?
- In extreme storms, ships may turn and travel in the same direction as the wind and waves are traveling, even if doing so takes them in almost the opposite direction from their intended course. Why do you think this might be safer than traveling into the wind and waves?
- Are there internal waves in the atmosphere? If so, where would you be most likely to find them? If there were internal waves in the atmosphere, would you expect their wavelengths to be longer or shorter than those of internal waves in the oceans? Why?