Numerade

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Paul Gabriel

Numerade educator

Two geological field teams are working in a remote area. A global positioning system (GPS) tracker at their base camp shows the location of the first team as 38 $\mathrm{km}$ away, $19^{\circ}$ north of west, and the second team as 29 km away, $35^{\circ}$ east of north. When the first team uses its GPS to check the position of the second team, what does the GPS give for the second team's (a) distance from them and (b) direction, measured from due east?

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Darshan Maheshwari

Numerade educator

A whole number increased by its square is two more than twice itself. Find the number.

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Catherine Lemar

Numerade educator

What theory did John Dalton formulate?

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Umar Sohail Qureshi

Numerade educator

(II) A meteorite has a speed of 90.0 $\mathrm{m} / \mathrm{s}$ when 850 $\mathrm{km}$ above the Earth. It is falling vertically (ignore air resistance) and strikes a bed of sand in which it is brought to rest in 3.25 $\mathrm{m}$ . (a) What is its speed just before striking the sand? (b) How much work does the sand do to stop the meteorite (mass $=575 \mathrm{kg}$ ? (c) What is the average force exerted by the sand on the meteorite? (d) How much thermal energy is produced?

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Umar Sohail Qureshi

Numerade educator

(III) A long copper strip 1.8 cm wide and 1.0 mm thick is placed in a 1.2-T magnetic field as in Fig. 20-21a. When a steady current of 15 A passes through it, the Hall emf is measured to be 1.02 $\mu$V. Determine ($a$) the drift velocity of the electrons and ($b$) the density of free (conducting) electrons (number per unit volume) in the copper. [$Hint:$ See also Section 18-8.]

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C D

Numerade educator

Knowing that the tension is 425 lb in cable $A B$ and 510 lb in cable $A C$ determine the magnitude and direction of the resultant of the forces exerted at $A$ by the two cables.

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Bryan Valdivia

Numerade educator

Which of the following statements about the DNA in one of your brain cells is true? \begin{equation} \begin{array}{l}{\text { (A) Most of the DNA codes for protein. }} \\ {\text { (B) The majority of genes are likely to be transcribed. }} \\ {\text { (C) It is the same as the DNA in one of your liver cells. }} \\ {\text { (D) Each gene lies immediately adjacent to an enhancer. }}\end{array} \end{equation}

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Vishal Gupta

Numerade educator

What are the three ways in which voltage can be induced in a loop of wire?

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Darshan Maheshwari

Numerade educator

Use the work$-$energy theorem to solve each of these problems. You can use Newton's laws to check your answers. (a) A skier moving at 5.00 m/s encounters a long, rough horizontal patch of snow having a coefficient of kinetic friction of 0.220 with her skis. How far does she travel on this patch before stopping? (b) Suppose the rough patch in part (a) was only 2.90 m long. How fast would the skier be moving when she reached the end of the patch? (c) At the base of a frictionless icy hill that rises at 25.0$^\circ$ above the horizontal, a toboggan has a speed of 12.0 m/s toward the hill. How high vertically above the base will it go before stopping?

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David Collins

Numerade educator

A coffee-cup calorimeter initially contains 125 $\mathrm{g}$ water at $24.2^{\circ} \mathrm{C} .$ Potassium bromide $(10.5 \mathrm{g}),$ also at $24.2^{\circ} \mathrm{C},$ is added to the water, and after the KBr dissolves, the final temperature is $21.1^{\circ} \mathrm{C}$ . Calculate the enthalpy change for dissolving the salt in $\mathrm{J} / \mathrm{g}$ and $\mathrm{kJ} / \mathrm{mol}$ . Assume that the specific heat capacity of the solution is 4.18 $\mathrm{J} / \mathrm{C} \cdot \mathrm{g}$ and that no heat is transferred to the surroundings or to the calorimeter.

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Dorothy M.