Numerade

Questions asked

ANSWERED

Taimoor Shabbir

Numerade educator

The mole is defined as the amount of a substance containing the same number of particles as exactly 12 g of C-12. The amu is defined as 1>12 of the mass of an atom of C-12. Why is it important that both of these definitions reference the same isotope? What would be the result, for example, of defining the mole with respect to C-12, but the amu with respect to Ne-20?

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Pritesh Ranjan

Numerade educator

A wheel of mass $M$ has radius $R$. It is standing vertically on the floor, and we want to exert a horizontal force $F$ at its axle so that it will climb a step against which it rests (Fig. 8-60). The step has height $h$, where $h < R$. What minimum force $F$ is needed?

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Ashwin Banarsee

Numerade educator

Use the fact that the speed of light in a vacuum is about $3.00 \times 10^{8} \mathrm{m} / \mathrm{s}$ to determine how many kilometers a pulse from a laser beam travels in exactly one hour.

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Babita Kumari

Numerade educator

Find each sum or difference. $$ 1.5-8.5 $$

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INSTANT ANSWER

Repeat Exercise 5 for a nonzero $3 \times 2$ matrix.

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ANSWERED

Ashwin Banarsee

Numerade educator

A person can survive a feet-first impact at a speed of about 12 $\mathrm{m} / \mathrm{s}(27 \mathrm{mi} / \mathrm{h})$ on concrete, 15 $\mathrm{m} / \mathrm{s}(34 \mathrm{mi} / \mathrm{h})$ on soil, and 34 $\mathrm{m} / \mathrm{s}(76 \mathrm{mi} / \mathrm{h})$ on water. What is the reason for the different values for different surfaces?

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INSTANT ANSWER

A 100-mL sample of hard water is titrated with the EDTA solution in Problem 2. The same amount of $\mathrm{Mg}^{2+}$ is added as previously, and the volume of EDTA required is $22.44 \mathrm{mL}$ a. What volume of EDTA is used in titrating the $\mathrm{Ca}^{2+}$ in the hard water? _______ $\mathrm{mL}$ b. How many moles of EDTA are there in that volume? _______ moles c. How many moles of $\mathrm{Ca}^{2+}$ are there in the $100 \mathrm{mL}$ of water? ______ moles d. If the $\mathrm{Ca}^{2+}$ comes from $\mathrm{CaCO}_{3}$, how many moles of $\mathrm{CaCO}_{3}$ are there in one liter of the water? How many grams CaCO_pcr litcr? ________ moles ______ $g$ e. If 1 ppm $\mathrm{CaCO}_{3}=1 \mathrm{mg}$ per liter, what is the water hardness in ppm $\mathrm{CaCO}_{3} ?$ ______ ppm $\mathrm{CaCO}_{3}$

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Rebecca Johnson

Numerade educator

A drawer contains an unorganized collection of 18 socks. Three pairs are red, two pairs are white, and four pairs are black. (a) If one sock is drawn at random from the drawer, what is the probability that it is red? (b) Once a sock is drawn and discovered to be red, what is the probability of drawing another red sock next to make a matching pair? (c) If two socks are drawn from the drawer at the same time, what is the probability that both are red?

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Ma Ednelyn Lim

Numerade educator

A cube of edge length $6.0 \times 10^{-6} \mathrm{m}$ emissivity $0.75,$ and temperature $-100^{\circ} \mathrm{C}$ floats in an environment at $-150^{\circ} \mathrm{C}$ . What is the cube's net thermal radiation transfer rate?

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ANSWERED

Umar Sohail Qureshi

Numerade educator

(II) Three blocks on a frictionless horizontal surface are in contact with each other as shown in Fig. $42 .$ A force $\vec{\mathbf{F}}$ is applied to block $\mathrm{A}$ (mass $m_{\mathrm{A}} )$ . (a) Draw a free-body diagram for each block. Determine $(b)$ the acceleration of the system (in terms of $m_{A}, m_{B},$ and $m_{C} ),(c)$ the net force on each block, and $(d)$ the force of contact that each block exerts on its neighbor. (e) If $m_{A}=m_{B}=m_{C}=10.0 \mathrm{kg}$ and $F=96.0 \mathrm{N},$ give numerical answers to $(b),(c),$ and $(d)$ . Explain how your answers make sense intuitively.

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Canary c.