Numerade

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Nicole Smina

Numerade educator

Two allotropes ( $A$ and $B$ ) of sulfur interconvert at $369 \mathrm{K}$ and 1 atm pressure:$$\mathrm{S}_{\mathrm{s}}(s, \mathrm{A}) \rightarrow \mathrm{S}_{\mathrm{g}}(s, \mathrm{B})$$.The enthalpy change in this transition is $297 \mathrm{J} / \mathrm{mol}$. What is the entropy change?

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Umar Sohail Qureshi

Numerade educator

An investigator measuring various characteristics of a large group of athletes found that the correlation between the weight of an athlete and the amount of weight that athlete could lift was $0.60 .$ True or false, and explain: (a) On the average, an athlete can lift 60$\%$ of his body weight. (b) If an athlete gains 10 pounds, he can expect to lift an additional 6 pounds. (c) The more an athlete weighs, on the average the more he can lift. (d) The more an athlete can lift, on the average the more he weighs. (e) 60$\%$ of an athlete's lifting ability can be attributed to his weight alone.

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Hubert Agamasu

Numerade educator

(II) The platter of the $\textbf{hard drive}$ of a computer rotates at 7200 rpm (rpm $=$ revolutions per minute $=$ rev/min). $(a)$ What is the angular velocity (rad/s) of the platter? $(b)$ If the reading head of the drive is located 3.00 cm from the rotation axis, what is the linear speed of the point on the platter just below it? $(c)$ If a single bit requires 0.50 $\mu$m of length along the direction of motion, how many bits per second can the writing head write when it is 3.00 cm from the axis?

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Satyam Gupta

Numerade educator

ELECTRIC CIRCUITS The current $I$ (in amperes) when 100 volts is applied to a circuit is given by $I = 5e^{-2t} sin\ t$, where $t$ is the time (in seconds) after the voltage is applied. Approximate the current at $t=0.7$ second after the voltage is applied.

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Juan Nicolás

Numerade educator

The price of aspirin rose sharply last month, while the quantity sold remained the same. Five people suggest various diagnoses of the phenomenon: MEREDTTH: $\quad$Demand increased, but supply was perfectly inelastic. Alex: $\quad$ Demand increased, but it was perfectly inelastic. MiranoA: $\quad$ Demand increased, but supply decreased at the same time. Rictaro: $\quad$ Supply decreased, but demand was unit elastic. Owen: $\quad$ Supply decreased, but demand was perfectly inelastic. Who could possibly be right? Use graphs to explain your answer.

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INSTANT ANSWER

Let $\mathbf{e}_{1}=\left[\begin{array}{l}{1} \\ {0}\end{array}\right], \mathbf{e}_{2}=\left[\begin{array}{l}{0} \\ {1}\end{array}\right], \mathbf{y}_{1}=\left[\begin{array}{c}{2} \\ {5}\end{array}\right],$ and $\mathbf{y}_{2}=\left[\begin{array}{r}{-1} \\ {6}\end{array}\right],$ and let $T : \mathbb{R}^{2} \rightarrow \mathbb{R}^{2}$ be a linear transformation that maps $\mathbf{e}_{1}$ into $\mathbf{y}_{1}$ and maps $\mathbf{e}_{2}$ into $\mathbf{y}_{2} .$ Find the images of $\left[\begin{array}{r}{5} \\ {-3}\end{array}\right]$ and $\left[\begin{array}{l}{x_{1}} \\ {x_{2}}\end{array}\right]$.

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Teresa Fuston

Numerade educator

Determine the domain and range of the quadratic function. $k(x)=3 x^{2}-6 x-9$

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INSTANT ANSWER

The flask (right) represents the products of the titration of 25 mL of sulfuric acid with 25 mL of sodium hydroxide. (a) Write balanced molecular, total ionic, and net ionic equations for the reaction. (b) If each orange sphere represents 0.010 mol of sulfate ion, how many moles of acid and of base reacted? (c) What are the molarities of the acid and the base?

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Umar Sohail Qureshi

Numerade educator

A $6 \times 12$ -in. plate is subjected to four loads as shown. Find the resultant of the four loads and the two points at which the line of action of the resultant intersects the edge of the plate. (Figure cant copy)

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Christopher Nilsen

Numerade educator

Challenge Vinegar is 5$\%$ acetic acid by mass and has a density of 1.02 $\mathrm{g} / \mathrm{mL}$ . What mass of acetic acid, in grams, is present in 185 $\mathrm{mL}$ of vinegar?

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Sean N.