Numerade

Questions asked

INSTANT ANSWER

Exercises 36–42 are puzzles that can be solved by translating statements into logical expressions and reasoning from these expressions using truth tables. Steve would like to determine the relative salaries of three coworkers using two facts. First, he knows that if Fred is not the highest paid of the three, then Janice is. Second, he knows that if Janice is not the lowest paid, then Maggie is paid the most. Is it possible to determine the relative salaries of Fred, Maggie, and Janice from what Steve knows? If so, who is paid the most and who the least? Explain your reasoning.

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ANSWERED

Bryan Valdivia

Numerade educator

A man with hemophilia marries a woman who has normal hemoglobin and is not a carrier. Which of the following is true? (A) None of their children will have the disease nor will they be carriers. (B) All the boys will have the disease. (C) All the girls will have the disease. (D) All the boys will be carriers. (E) All the girls will be carriers.

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ANSWERED

Umar Sohail Qureshi

Numerade educator

In Example $21.4,$ suppose the point charge on the $y$ -axis at $y=-0.30 \mathrm{m}$ has negative charge $-2.0 \mu \mathrm{C},$ and the other charges remain the same. Find the magnitude and direction of the net force on $Q .$ How does your answer differ from that in Example 21.4 ? Explain the differences.

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ANSWERED

Michael Sorola

Numerade educator

A hydrogen atom is about $0.1 \mathrm{nm}$ in diameter. How many hydrogen atoms lined up side by side would make a line $1 \mathrm{cm}$ long?

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INSTANT ANSWER

In Fig. $22-64 a,$ a particle of charge $+Q$ produces an electric field of magnitude $E_{\text { part }}$ at point $P,$ at distance $R$ from the particle. In Fig. $22-64 b,$ that same amount of charge is spread uniformly along a circular arc that has radius $R$ and subtends an angle $\theta$ The charge on the arc produces an electric field of magnitude $E_{\mathrm{arc}}$ at its center of curvature $P .$ For what value of $\theta$ does $E_{\text { arc }}=$ 0.500$E_{\text { part? }}$ (Hint: You will probably resort to a graphical solution.)

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ANSWERED

Umar Sohail Qureshi

Numerade educator

The inductor shown in Fig. 30.18 has inductance 0.260 $\mathrm{H}$ and carries a current in the direction shown. The current is changing at a constant rate. (a) The potential between points $a$ and $b$ is $V_{a b}=1.04 \mathrm{V},$ with point $a$ at higher potential. Is the current increasing or decreasing? b) If the current at $t=0$ is 12.0 $\mathrm{A}$ , what is the current at $t=2.00 \mathrm{s} ?$

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ANSWERED

David Mccaslin

Numerade educator

The following graph of the function $f$ satisfies $$\lim _{x \rightarrow 2} f(x)=2 .$$ In the following exercises, determine a value of $\delta>0$ that satisfies each statement. If $0<|x-2|<\delta,$ then $|f(x)-2|<0.5$

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ANSWERED

Ma Ednelyn Lim

Numerade educator

A device for training astronauts and jet fighter pilots is designed to move the trainee in a horizontal circle of radius 11.0 m. If the force felt by the trainee is 7.45 times her own weight, how fast is she revolving? Express your answer in both m/s and rev/s.

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INSTANT ANSWER

In Examples 1 we used Lotka-Volterra equations to model populations of rabbits and wolves. Let's modify those equations as follows: $ \frac {dR}{dt} = 0.08R(1 - 0.0002R) - 0.001RW $ $ \frac {dW}{dt} = -0.02W + 0.00002RW $ (a) According to these equations, what happens to the rabbit population in the absence of wolves? (b) Find all the equilibrium solutions and explain their significance. (c) The figure shows the phase trajectory that starts at the point (1000, 40). Describe what eventually happens to the rabbit and wolf populations. (d) Sketch graphs of the rabbit and wolf populations as function of time.

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ANSWERED

Prabhat Tyagi

Numerade educator

In the ground state of hydrogen, the uncertainty in the position of the electron is roughly 0.10 nm. If the speed of the electron is approximately the same as the uncertainty in its speed, about how fast is it moving?

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Christopher H.