Harbor seals, like many animals, determine the direction from which a sound is coming by sensing the difference in arrival times at their two ears. A small difference in arrival times means that the object is in front of the seal; a larger difference means it is to the left or right. There is a minimum time difference that a seal can sense, and this leads to a limitation on a seal's direction sense. Seals can distinguish between two sounds that come from directions $3 ^ { \circ }$ apart in air, but this increases to $9 ^ { \circ }$ in water. Explain why you would expect a seal's directional discrimination to be worse in water than in air.

Which of the terms you listed in your Reader's Notebook relate to citizens' rights? Explain how these rights influenced the outcome of Anthony's case.

A laser beam has intensity $I _ { 0 }$. a. What is the tensity, in terms of $I _ { 0 }$, if a lens focuses the laser beam to 1/10 its initial diameter? b. What is the intensity, in terms of $I _ { 0 }$, if a lens defocuses the laser beam to 10 times its initial diameter?

A copper block is removed from a $300^{\circ} \mathrm{C}$ oven and dropped into 1.00 kg of water at $20.0^{\circ} \mathrm{C}$. Th water quickly reaches $25.5^{\circ} \mathrm{C}$ and then remains at that temperature. What is the mass of the copper block?

Find the eigenvalues and corresponding eigenvectors of the matrices (a)

$$\left[ \begin{array}{ll}{1} & {1} \\ {1} & {1}\end{array}\right] \quad \text { (b) } \left[ \begin{array}{ll}{1} & {2} \\ {3} & {2}\end{array}\right]$$

(c)

$$\left[ \begin{array}{rrr}{1} & {0} & {-4} \\ {0} & {5} & {4} \\ {-4} & {4} & {3}\end{array}\right] \quad \text { (d) } \left[ \begin{array}{rrr}{1} & {1} & {2} \\ {0} & {2} & {2} \\ {-1} & {1} & {3}\end{array}\right]$$

(e)

$$\left[ \begin{array}{rrr}{5} & {0} & {6} \\ {0} & {11} & {6} \\ {6} & {6} & {-2}\end{array}\right] \quad(\mathrm{f}) \left[ \begin{array}{rrr}{1} & {-1} & {0} \\ {1} & {2} & {1} \\ {-2} & {1} & {-1}\end{array}\right]$$

(g)

$$\left[ \begin{array}{ccc}{4} & {1} & {1} \\ {2} & {5} & {4} \\ {-1} & {-1} & {0}\end{array}\right] \quad \text { (h) } \left[ \begin{array}{rrr}{1} & {-4} & {-2} \\ {0} & {3} & {1} \\ {1} & {2} & {4}\end{array}\right]$$

A laser beam has intensity $I_0$. a. What is the intensity, in terms of $I_0$, if a lens focuses the laser beam to $\frac{1}{10}$ its initial diameter? b. What is the intensity, in terms of $I_0$, if a lens defocuses the laser beam to 10 times its initial diameter?

Before the 2003 Super Bowl, ABC predicted that 22% of the Super Bowl audience would express an interest in seeing one of its forthcoming new television shows, including 8 Simple Rules, Are You Hot?, and Dragnet. ABC ran commercials for these television shows during the Super Bowl. The day after the Super Bowl, Intermediate Advertising Group of New York sampled 1532 viewers who saw the commercials and found that 414 said that they would watch one of the ABC advertised television shows (The Wall Street Journal, January 30, 2003). a. What is the point estimate of the proportion of the audience that said they would watch the television shows after seeing the television commercials? b. At $\alpha$= .05, determine whether the intent to watch the ABC television shows significantly increased after seeing the television commercials. Formulate the appropriate hypotheses, compute the p-value, and state your conclusion. c. Why are such studies valuable to companies and advertising firms?

There are two carotid arteries that feed blood to the brain, one on each side of the neck and head. One patient's carotid arteries are each 11.2 cm long and have an inside diameter of 5.2 mm. Near the middle of the left artery, however, is a 2.0-cm-long stenosis, a section of the artery with a smaller diameter of 3.4 mm, For the same blood flow rate, what is the ratio of the pressure drop along the patient's left carotid artery to the drop his right artery?

Two strings of different linear densities are joined together and pulled tautly. A sinusoidal wave on these strings is traveling to the right, as shown in what we discussed earlier. When the wave goes across the boundary from string 1 to string 2, the frequency is unchanged. What happens to the velocity?
A. The velocity increases.
B. The velocity stays the same.
C. The velocity decreases.

A mass on a string of unknown length oscillates as a pendulum with a period of 4.00 s. What is the period if a. The mass is doubled? b. The string length is doubled? c. The string length is halved? d. The amplitude is halved? Parts a to d are independent questions, each referring to the initial situation.

In a darkened room, red light shines on a red cup, white card, and a blue toy. The cup, card, and toy will appear, respectively., A. Red, red, blue. B. Red, white, blue. C. Red, red, black. D. Red, black, blue.

Bottlenose dolphins use echolocation pulses with a frequency of about 100 kHz, higher than the frequencies used by most bats. Why might you expect these water-dwelling creatures to use higher echolocation frequencies than bats?

In the aftermath of an intense earthquake, the earth as a whole "rings" with a period of 54 minutes. What is the frequency (in Hz) of this oscillation?

A diver 50 m deep in $10^{\circ} \mathrm{C}$ fresh water exhales a 1.0-cm-diameter bubble. What is the bubble's diameter just as it reaches the surface of the lake, where the water temperature is $20^{\circ} \mathrm{C}$? HInt: Assume that the air bubble is always in thermal equilibrium with the surrounding water.