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3 years ago

Math phys can i have help 7-10

Physics

1 answer:

Vladimir79 [104]3 years ago

4 0

Answer:

007. 4. 124.091

008. 9. 0.232679738562091

009. 1. 66.8457608738846

010. 3. 14.2 N

Explanation:

007. Speed of a wave is the product of its wavelength and it frequency.

v = λ f

For a given velocity, the minimum frequency occurs at the maximum wavelength.

For a standing wave, the distance between the nodes (fixed points that don't oscillate) is a multiple of half the wavelength.

L = k/2 λ

The wavelength is a maximum at k=1 (also known as the first harmonic).

L = 1/2 λ

λ = 2L

Substituting and solving for f:

v = 2L f

f = v / (2L)

f = 546 m/s / (2 × 2.2 m)

f = 124.091 Hz

008. The sound travels from the dolphin to the ocean floor, then back to the dolphin. So it travels a total distance of 2 × 178 m = 356 m. At a speed of 1530 m/s, the time it takes for the sound to travel this distance is:

t = d / v

t = 356 m / 1530 m/s

t = 0.232679738562091 s

009. Sound intensity in decibels is:

I(db) = 10 log(I / I₀)

where I is the sound intensity (W/m²) and I₀ is the threshold of hearing.

We know that the sound intensity I is proportional to the number of cars per minute. If we say n is the number of cars per minute, and k is the constant of proportionality, then:

I(db) = 10 log(kn / I₀)

When n = 132, I = 73.

73 = 10 log(132k / I₀)

7.3 = log(132k / I₀)

10^7.3 = 132k / I₀

k / I₀ = (10^7.3) / 132

k / I₀ = 151156.236

So the equation for intensity in decibels is:

I(db) = 10 log(151156.236 n)

When n = 32:

I(db) = 10 log(151156.236 × 32)

I(db) = 66.8457608738846

010. For a vibrating string, the tension is:

T = v² m/L

where v is the speed and m/L is the mass per length of the string.

When v = 18.6, T = 6.43.

6.43 = (18.6)² m/L

m/L = 0.01859

So the equation is:

T = 0.01859 v²

When v = 27.6:

T = 0.01859 (27.6)²

T = 14.2 N

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In the Bohr model of the atom, atomic electrons approximatately 'orbit' the nucleus. The hydrogen atom consists of a proton of m

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Answer:

$F=3.61\times 10^{-47}\ N$

Explanation:

Mass of a proton, $m_p=1.67\times 10^{-27}\ kg$

Mass of an electron, $m_e=9.11\times 10^{-31}\ kg$

The distance between the electron and the proton is, $r=5.3\times 10^{-11}\ m$

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$F=G\dfrac{m_em_p}{r^2}$

Where G is the universal Gravitational constant

$F=6.67\times 10^{-11}\times \dfrac{9.11\times 10^{-31}\times 1.67\times 10^{-27}}{(5.3\times 10^{-11})^2}\\\\F=3.61\times 10^{-47}\ N$

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3 years ago

Each of the four expansion models (recollapsing, critical, coasting, and accelerating) predict different ages for the universe,

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Answer:

This is because the age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

Explanation:

The age of the universe is determined by the pace of expansion in the past, and each model forecasts a different pace.

This is due to the fact that the expansion rate in the coasting model is constant and never changes. Because the cosmos is growing faster now than during the old days, recollapsing and critical models give shorter ages. According to the accelerating model, the universe is growing at a slower rate currently than in the past, implying an older age.

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3 years ago

What happens to the energy of a wave as it moves away from its source?

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Answer:

As the particles move further away from their normal position (up towards the wave crest or down towards the trough), they slow down.

Explanation:

This means that some of their kinetic energy has been converted into potential energy – the energy of particles in a wave oscillates between kinetic and potential energy. Hope that this helps you and have a great day :)

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3 years ago

Consider a situation of simple harmonic motion in which the distance between the endpoints is 2.39 m and exactly 8 cycles are co

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Answer:

1.195 m

2.8375 s

2.21433 rad/s

Explanation:

d = Distance = 2.39 m

N = Number of cycles = 8

t = Time to complete 8 cycles = 22.7 s

Radius would be equal to the distance divided by 2

$r=\frac{d}{2}\\\Rightarrow r=\frac{2.39}{2}\\\Rightarrow r=1.195\ m$

The radius is 1.195 m

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$T=\frac{t}{N}\\\Rightarrow T=\frac{22.7}{8}\\\Rightarrow T=2.8375\ s$

Time period of the motion is 2.8375 s

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3 years ago

When changing a tire sized 195/75 R15 to a 5 percent lower profile, the correct tire size would be _____

valentinak56 [21]

Answer and explanation:

When you are changing a car tire, the most important thing is to keep the total diameter as equal as possible.

The total car tire diameter can be calculated as:

$D_{tot orig}=\frac{195 \cdot 75}{2540 \cdot 2}+15''=26.5''$

The profile of this tire is 75 (the higher/taller relation), therefore a 5 percent lower profile would be:

pr=0.95·75=71.25

The problem is that the profiles are normalized and the nearest profile available is 70.

If we take a theorical tire with a profile of 71.25:

$D_{tot orig}=D_{new}\\\frac{195 \cdot 75}{2540 \cdot 2}+15''=\frac{X \cdot 71.25}{2540 \cdot 2}+15''\\X=205.26$

The theorical tire size should be 205/71 R15.

If we look for a real tire size, we should look for a tire with a diameter nearest to 26.5'' and a profile of 70.

The best option for real tire size is: Tire 225/70 R14 (wheel diameter of 26.4'') or 205/70 R15 (wheel diameter of 26.3'').

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3 years ago