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3 years ago

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A 60-vibration-per-second wave travels 30 meters in 1 second. Its frequency isA) 30 hertz and it travels at 60 m/s.B) 60 hertz a

nd it travels at 30 m/s.C) 1800 hertz and it travels at 2 m/s.

1 answer:

fredd [130]3 years ago

3 0

Answer:

B) 60 hertz and it travels at 30 m/s

Explanation:

The frequency of a wave corresponds to the number of complete vibrations per second. The wave in this problem has 60 vibrations per second, so its frequency is

$f=\frac{60 vibrations}{ 1 s}=60 Hz$

The speed of the wave instead is given by the distance travelled divided by the time taken. In this problem:

d = distance travelled = 30 m

t = time taken = 1 s

So, the speed of the wave is

$v=\frac{d}{t}=\frac{30 m}{1 s}=30 m/s$

so, the correct answer is

B) 60 hertz and it travels at 30 m/s

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Atom X contains seven protons and seven neutrons. atom Z contains seven protons and eight neutrons. which of the following state

stiks02 [169]

Answer:

The correct answer is option A: they are isotopes.

Explanation:

From atom X we know that the number of protons is 7 and the number of neutrons is 7 and from atom Z we know that the number of protons is 7 and the number of neutrons is 8.

Since the number of protons of atom X and atom Z is the same, we have that atom X and atom Z is the same element. The difference in the number of neutrons tells us that atom X and atom Z are isotopes. Remember that an isotope is one element that has atoms with different numbers of neutrons.

The mass number is given by:

$A = p + n$

Where <em>n</em> is the number of neutrons and <em>p </em>is the number of protons.

For atom X and atom Z we have:

$A_{x} = 7 + 7 = 14$

$A_{z} = 7 + 8 = 15$

Hence, they have a different mass number.

We know that the element with 7 protons is nitrogen. The first isotope is $^{14}_{7}N$ and the second isotope is $^{15}_{7}N$ . Both isotopes are stables (they are not radioactive).

Therefore, the correct answer is option A: they are isotopes.

I hope it helps you!

3 0

3 years ago

A magnetic field of 37.2 t has been achieved at the mit francis bitter national magnetic laboratory. Find the current needed to

jeka57 [31]

Answer:

Here is the complete question:

https://www.chegg.com/homework-help/questions-and-answers/magnetic-field-372-t-achieved-mit-francis-bitter-national-magnetic-laboratory-find-current-q900632

a) Current for long straight wire $=3.7\ MA$

b) Current at the center of the circular coil $=2.48\times 10^{5}\ A$

c) Current near the center of a solenoid $236.8\ A$

Explanation:

⇒ Magnetic Field due to long straight wire is given by (B),where $B=\frac{\mu\times I}{2\pi(r) },so\ I=\frac{B\ 2\pi(r)}{\mu}$

$\mu=4\pi \times 10^{-7}\ \frac{henry}{m}$

Plugging the values,

Conversion $1\times 10^6 A = 1\ MA$ ,and $2cm=\frac{2}{100}=0.02\ m$

$I=\frac{37.2\times \ 2\pi(0.02)}{4\ \pi \times (10^{-7})}=3.7\ MA$

⇒Magnetic Field at the center due to circular coil (at center) is given by, $B=\frac{\mu\times I (N)}{2(a)}$

So $I= \frac{2B(a)}{\mu\ N} = \frac{2\times 37.2\times 0.42}{4\pi\times 10^{-7}\times 100}=2.48\time 10{^5}\ A$

⇒Magnetic field due to the long solenoid, $B=\mu\ nI=\mu (\frac{N}{l})I$

Then $I=\frac{B}{\mu(\frac{N}{L})} \approx 236.8\A$

So the value of current are $3.7 MA$ , $2.48\times 10^{5} A$ and $236.8\ A$ respectively.

8 0

2 years ago

Which statement best describes particles that are affected by the strong

Eddi Din [679]

Answer: I think it’s D.

Explanation:

4 0

2 years ago

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speed of sound is 343 Ms at 20 degrees Celsius. The frequency heard from the sound is 256 Hz. what is the sounds wavelength?

Lina20 [59]

S= 343m/s
F=256Hz

WL= 343ms/256-1
WL=V/F

= 1.339844m

7 0

2 years ago

A 49 kg person is being dragged in their sleeping bag to the lake by a 593 N

crimeas [40]

Answer:

f = 485.62 N

Explanation:

Since, the bag is moving with some acceleration. Hence, the unbalanced force will be given as:

Unbalanced Force = Horizontal Component Applied Force - Frictional Force

Unbalanced Force = Fx - f

But, from Newtons Second Law of Motion:

Unbalanced Force = ma

comparing the equations:

ma = Fx - f

f = F Cos θ - ma

where,

f = frictional force = ?

F = Applied force = 593 N

m = mass of person = 49 kg

a = acceleration = 0.57 m/s²

θ = Angle with horizontal = 30°

Therefore,

f = (593 N)(Cos 30°) - (49 kg)(0.57 m/s²)

f = 513.55 N - 27.93 N

<u>f = 485.62 N</u>

6 0

3 years ago