Numerade

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Bryce Werts

Numerade educator

Why do we use carbon-12 rather than ordinary carbon as the basis for the mole?

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INSTANT ANSWER

MODELING WITH MATHEMATICS Planes That high speeds and low elevations have radar systems that can determine the range of an obstacle and the angle of elevation to the top of the obstacle. The radar of a plane $[\text { ying at an altitude of } 20,000 \text { feet detects }$ a tower that is $25,000$ feet away, with an angle of elevation of $1^{\circ}$ .

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Teresa Fuston

Numerade educator

In Exercises 5–10, describe and graph the interval of real numbers. $x$ is greater than or equal to 2 and less than or equal to $6 .$

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Albert Tres

Numerade educator

A sport utility vehicle that costs $ \$23,300 $ new has a book value of $ \$12,500 $ after $ 2 $ years. (a) Find the linear model $ V = mt + b $. (b) Find the exponential model $ V = ae^{kt} $. (c) Use a graphing utility to graph the two models in the same viewing window. Which model depreciates faster in the first $ 2 $ years? (d) Find the book values of the vehicle after $ 1 $ year and after $ 3 $ years using each model. (e) Explain the advantages and disadvantages of using each model to a buyer and a seller.

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Ashwin Banarsee

Numerade educator

Suppose a car manufacturer tested its cars for front-end collisions by hauling them up on a crane and dropping them from a certain height. (a) Show that the speed just before a car hits the ground, after falling from rest a vertical distance $H,$ is $sqrt{2 g H}$ . What height corresponds to a collision at $(b) 60 mathrm{km} / mathrm{h} ?(c) 100 mathrm{km} / mathrm{h} ?$

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Ryan Swift

Numerade educator

Which of these statements is not one of the financial statements? A. income statement B. balance sheet C. statement of cash flows D. statement of owner investments

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Ashwin Banarsee

Numerade educator

A rectangle has a length of $(2.0 \pm 0.2) \mathrm{m}$ and a width of $(1.5$ $\pm 0.1 ) \mathrm{m}$ . Calculate (a) the area and (b) the perimeter of the rectangle, and give the uncertainty in each value.

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Nicole Smina

Numerade educator

What are the cations and anions whose compounds are usually soluble? What are the exceptions? What are the anions whose compounds are mostly insoluble? What are the exceptions?

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Ashwin Banarsee

Numerade educator

A U.S. penny has a diameter of 1.9000 cm at 20.0$^\circ$C. The coin is made of a metal alloy (mostly zinc) for which the coefficient of linear expansion is $2.6 \times 10{^-}{^5} K{^-}{^1}$. What would its diameter be on a hot day in Death Valley (48.0$^\circ$C)? On a cold night in the mountains of Greenland (-53$^\circ$C)?

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INSTANT ANSWER

In a hypothetical research situation, scientists discover bacterial endospores in silt at the bottom of a marsh that has been contaminated with a pollutant for 25 years. The silt of the marsh was deposited in annual layers. The age of the endospores can be estimated, then, by identifying the layer of silt in which the endospores are found. In flask A, researchers place 20-year-old endospores along with growth medium and the pollutant. In flask B, researchers place 100-year-old endospores along with growth medium and the pollutant. Suppose the researchers observe the flasks for a while, continuing to replenish growth medium and pollutant as necessary. Which statement describes the results you would expect to see in the growth of the flasks after some time? a. The growth in flask A will continue to exceed that of flask $\mathrm{B}$ . b. The growth in flask $\mathrm{B}$ will exceed continue to exceed that of flask A. c. Eventually, the difference in the growth in each d. Eventually, will be little to no growth in each flask.

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Jessica A.