A setting Sun appears red due to the
a. scattering of lower frequencies by larger particles in the air.
b. light's longer path through the air at sunset.
c. absorption by smaller particles in the air.
d. lower frequencies of light emitted during sunset.

The wavelength of an ultrasound with a frequency of 4.257 MHz in the human body is approximately 0.000249 meters or 0.249 mm, calculated using the formula
λ = v/f with the given speed of sound (1060 m/s) and the frequency.

The question is asking to calculate the wavelength of an ultrasound with a frequency of 4.257 MHz in the human body, given the speed of sound in the body is 1.06 km/s. To find the wavelength, we use the formula λ = v/f, where λ is the wavelength, v is the speed of sound, and f is the frequency.

First, we convert the speed of sound from km/s to m/s: 1.06 km/s = 1060 m/s. Then we use the given frequency (f) of 4.257 MHz, which we also convert to Hz: 4.257 MHz = 4.257 x 106 Hz. Now we can calculate the wavelength:

λ = v/f
λ = 1060 m/s / 4.257 x 106 Hz
λ ≈ 0.000249 m

Therefore, the wavelength of the ultrasound in the body is approximately 0.000249 meters or 0.249 mm.

The wavelength of 4.257 MHz ultrasound in the human body, using the speed of sound of 1.06 km/s, is approximately 0.249 mm.

To determine the wavelength of ultrasound in the body given the frequency and the speed of sound, we can use the formula:
lambda = v / f, where
lambda is the wavelength,
v is the speed of sound, and
f is the frequency of the ultrasound wave. The speed of sound in the body is given as 1.06 km/s, which is equivalent to 1060 m/s. The frequency of the ultrasound is 4.257 MHz, or 4.257 x 106 Hz. Plugging these values into the formula:

lambda = 1060 m/s / 4.257 x 106 Hz

The result will yield the wavelength of ultrasound in the human body, measured in meters.

Performing the calculation:
lambda = 1060 / 4.257 x 106
lambda = 0.000249 m or approximately 0.249 mm

The wavelength of 4.257 MHz ultrasound in the human body is therefore about 0.249 mm.

Tarzan's speed just before his feet touch the ground is 7.4 m/s, calculated using conservation of energy. The net change in internal energy as he bends his knees and stops is 2603.4 J, equivalent to the loss of kinetic energy.

Part (a): Speed of Tarzan Before Touchdown

To find the speed of Tarzan just before his feet touch the ground, we can use the principle of conservation of energy. Initially, Tarzan has gravitational potential energy due to being at a height of 2.8 m above the ground. When he lets go, this potential energy converts to kinetic energy as he falls. At the instant before his feet touch the ground, he is at a height of 0.8 m (2.8 m - 2 m), and the gravitational potential energy at this point converts into kinetic energy. Using the conservation of energy:

Initial Potential Energy = Final Kinetic Energy

mghinitial = 1/2*mv^2


Plugging in the values:
94 kg × 9.8 m/s2 × 2.8 m = (1/2) × 94 kg × v2

After solving the equation, we find:

v = 7.4 m/s

Part (b): Net Change in Internal Energy

The net change in internal energy is the difference between the kinetic energy just before the feet touch the ground and the energy when Tarzan is crouched. Assuming no losses, all the kinetic energy converts into internal energy. Without specific details on work done by Tarzan to flex his muscles or any other form of energy conversion, the kinetic energy that is no longer present in the motion would be assumed to convert fully to internal energy (such as heat). The net change in internal energy equates to the kinetic energy which is lost:

Change in Internal Energy = 1/2*mv^2 - 0 J, since he is at rest.

Using the speed found in part (a) and Tarzan's mass: 1/2*× 94 kg × (7.4 m/s)2

This calculation results in a net change in internal energy of: 2603.4 J

Answer:

12 RPM

Explanation:

I would calculate the distance from the edge to the center, and then multiple that by 3RPM with 2 m/sec

Answer:

A) energy similar to radiant heat from the sun

Answer:

a) 0.3965 j

b) 0.3112 m

Explanation:

The picture attached explains it all. Thank you

Answer:

Asthenosphere

Explanation:

The asthenosphere is a part of the upper mantle just below the lithosphere that is involved in plate tectonic movement and isostatic adjustments.

Answer:

  (c)  n1 = n2

Explanation:

You want to know what can be said about the indices of refraction when a light ray continues on a straight path from one medium to another.

When a wave passes through media where the index of refraction changes, its path will be bent in accordance with Snell's law. When the index of refraction does not change, the path will remain unbent.

The figure shows the path of the ray is a straight line, so we can conclude ...

  n1 = n2 . . . . . choice C

__

Additional comment

Even if the indices are different, the path will remain straight if the angle of incidence is 0—the path is normal to the interface between media. Here, the path is not shown as normal to the interface.

Answer:

[tex]1.8\times 10^{-5}/K[/tex]

Explanation:

Volume of glass flask,[tex]V_0=1000 cm^3[/tex]

[tex]T_1=1.00^{\circ} C[/tex]

[tex]T_2=52.0^{\circ} C[/tex]

Over flow[tex]\Delta V=8.25 cm^3[/tex]

Coefficient of mercury=[tex]\beta_{Hg}=18.0\times 10^{-5}/K[/tex]

[tex]\Delta V_{Hg}=\beta_{Hg}V_0(T_2-T_1)=18\times 10^{-5}\times 1000\times (52-1)[/tex]

[tex]\Delta V_{Hg}=9.18 cm^3[/tex]

[tex]\Delta_{gass}=\Delta V-\Delta_{Hg}=9.18-8.25=0.93 cm^3[/tex]

[tex]\beta_{gass}=\frac{\Delta V_{gass}}{V_0(T_2-T_1)}[/tex]

[tex]\beta_{gass}=\frac{0.93}{1000\times (52-1)}[/tex]

[tex]\beta_{gass}=1.8\times 10^{-5}/K[/tex]

Hence, the coefficient of volume expansion of the glass=[tex]1.8\times 10^{-5}/^{\circ} C[/tex]

The coefficient of volume expansion of the glass [tex]\bold { 1.8 x 10^-^5\ K^-^ 1}[/tex]

Given here,

Volume of the glass flask = 1000[tex]\bold {cm^3}[/tex]

Initial temperature = 1[tex]\bold{^oC}[/tex]

Final temperature = 52 [tex]\bold{^oC}[/tex]

[tex]\bold{ \Delta V = V_0 \beta \Delta T}[/tex]

Where,

[tex]\bold {\Delta V}[/tex] - Change in volume

[tex]\bold{V_0}[/tex] - initial volume = 1000cm

[tex]\bold {\beta }[/tex] -  coefficient of volume expansion

[tex]\bold{\Delta T }[/tex] - temperature [tex]\bold { = T_2- T_1}[/tex]

Put the values in the formula

[tex]\bold {\Delta V_H_g = 18\times 10^-^5 \times 1000\times 51}\\\\\bold {\Delta V_H_g = 9.18 cm^3}[/tex]

[tex]\bold {\Delta Vglass = \Delta V_H_g - \Delta _H_g}\\\\\bold {\Delta Vglass = 9.18 -8.25 }\\\\\bold {\Delta Vglass = 0.93 cm^3}[/tex]

So,  coefficient of volume expansion for gas,

[tex]\bold {\beta glass = \dfrac {0.93 }{1000 \times 51}}\\\\\bold {\beta glass = 1.8 x 10^-^5\ K^-^ 1}[/tex]

The coefficient of volume expansion of the glass [tex]\bold { 1.8 x 10^-^5\ K^-^ 1}[/tex]

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Answer:

Speed of light changes

Explanation:

Since glass is denser than air so the speed of light in glass is less than in air so light rays bend i.e. refract.

Light refracts when traveling from air into glass due to a change in speed caused by differences in optical density. The process, governed by Snell's Law, results in the bending of light towards the normal line as it enters the denser medium.

Light refracts when traveling from air into glass because light waves undergo a change in speed when they pass from one medium to another. This process is known as refraction. Refraction occurs because there is a change in light's propagation speed due to the difference in optical density between air and glass. When light rays propagate from air (less optically dense) into glass (more optically dense), they bend towards the normal line—a line perpendicular to the boundary between the two media. This bending happens according to Snell's Law, which relates the angle of incidence to the angle of refraction, taking into account the refractive indices of the two media.

Answer:

Explanation:

Given that,

The speed of the car is

Vc = 97m/s

The radius of circular path of the car is

Rc = 420m

We want to find the angle of roadway banked β?

To determine the angle of roadway banked, we will use the formula

tanβ = Vc² / Rc•g

Where Vc = 97m/s, Rc = 420m and

g = 9.8m/s²

Then

tanβ = 97² / (420 × 9.8)

tanβ = 2.28596

β = ArcTan ( 2.28596)

β = 66.37°

The railway banked at an angle of 66.37°

Answer:

Banking angle is 66.35°

Explanation:

Given radius r=420m

Speed=97m/s

banking angle is A

Note before

(V)=√(r*gtanA)

√97=√420*9.81*tanA)taking square of both sides

97^2=420*9.81*tan A.

tanA=66.35°

A=66.35°

Answer:

6.0?

Explanation:

What is the current in this circuit?

A

Hold on, our servers are swamped. Wait for your answer to fully load.

Answer:

The first one is 15.

The second one is 3.0.

Explanation:

You add up all the sides accept the voltage. 2+3+4+6= 15

For the second one you divide the voltage by all the resisters. 45/15=3

Answer:

A) volume flow rate = 0.047 m3/s

B) mass flow rate = 39.01 kg/s

Explanation:

Detailed explanation and calculation is shown in the image below

Answer: B

Explanation:

Answer:

Both Technicaian A and B is correct

Explanation:

An alternator is a device that converts mechanical energy into electrical energy. In every alternator, there is unavoidable power losses. Such losses could be mechanical,drive belt or getting the alternator's bearing heated and electrical loss.more also changing magnetic field also causes some losses in an alternator. The diodes of an alternator get hot when there is drop in votage.At reasonable maximum engine speeds, For instance when it read 1500 RPM to redline and there is heavy loads, starting from the idle through the red line with light electrical accessory loads, Nothing will happen to battery, it will just goes along for the ride. Unless it wait for the alternator to fall below operating speeds.

Therefore, when technician A says that to perform a maximum output test on a typical heavy-duty truck charging circuit, the engine should be run at 1500 rpm, and Technician B says that alternator rpm is typically at least three times engine rpm. Both of them is is correct.

Answer:

joule

Explanation:

every unit for Energy is joule J

Explanation:

Given that,

Diameter of the gold wire, d = 0.84 mm

Radius, r = 0.42 mm

Electric field in the wire, E = 0.49 V/m

(a) Electric current density is given by :

[tex]J=\dfrac{I}{A}[/tex]

And electric field is :

[tex]E=\rho J[/tex]

[tex]\rho[/tex] is resistivity of Gold wire

So,

[tex]E=\dfrac{\rhi I}{A}\\\\I=\dfrac{EA}{\rho}\\\\I=\dfrac{0.49\times \pi (0.42\times 10^{-3})^2}{2.44\times 10^{-8}}\\\\I=11.12\ A[/tex]

(b) The potential difference between two points in the wire is given by :

[tex]V=E\times l\\\\V=0.49 \times 6.4\\\\V=3.136\ V[/tex]

(c) Resistance of a wire is given by :

[tex]R=\rho \dfrac{l}{A}\\\\R=2.44\times 10^{-8}\times \dfrac{6.4}{\pi (0.42\times 10^{-3})^2}\\\\R=0.281\ \Omega[/tex]

Hence, this is the required solution.

Final answer:

To find the current carried by the gold wire, use Ohm's law. To find the potential difference between two points in the wire 6.4 m apart, multiply the electric field by the distance. To find the resistance of a 6.4-m length of the wire, use the formula R = ρL/A.

Explanation:

To find the current carried by the gold wire, we can use Ohm's law which states that the electric field (E) is equal to the product of the current (I) and the resistance (R) of the wire. Rearranging the equation, we can solve for the current: I = E/R. Given that the diameter of the wire is 0.84 mm, we can calculate the cross-sectional area using the formula for the area of a circle (A = πr^2). With the cross-sectional area, we can find the resistance by using the formula R = ρL/A, where ρ is the resistivity of gold and L is the length of the wire. Finally, we can substitute the values into the equation to find the current carried by the wire.

(b) To find the potential difference between two points in the wire 6.4 m apart, we can multiply the electric field by the distance between the two points: V = E × d.

(c) The resistance of a 6.4-m length of this wire can be found using the formula R = ρL/A, where ρ is the resistivity of gold, L is the length of the wire, and A is the cross-sectional area of the wire.

Answer:

T = 74.3N

Explanation:

We are given;

v(t) = (2.00m/s²)t+(0.600m/s³)t²

So, when v = 9 m/s;

9 = 2t + 0.6t²

0.6t² + 2t - 9 = 0

Solving this quadratic equation,

t = -5.88 or 2.55

We'll pick t = 2.55 s

Now, kinematic acceleration will be the derivative of the acceleration.

Thus, a = dv/dt = 2 + 1.2t

So, acceleration at that time t = 2.55s is; a = 2 + 1.2(2.55) = 5.06 m/s²

Since the rope is subject to both acceleration and gravity, Tension is;

T = mg + ma

T = m(g + a)

T = 5(9.8 + 5.06)

T = 74.3N

Errors in an experiment can include improperly calibrated equipment, human error in measurement timing, and uncontrolled conditions. To reduce these errors, calibration, multiple trials, and consistent variables can be used. Recognizing whether the results are qualitative or quantitative helps in addressing the impacts of these errors.

When considering the question of what best describes an error the students made in the experiment, we can refer to common sources of experimental error. These can vary widely but often include issues with the methods used, errors with the apparatus, or uncontrolled conditions within the experiment. For instance, students may have used improperly calibrated equipment like an electronic balance, leading to systematic errors in measurement. Furthermore, the timing of events using devices like stopwatches can introduce human error if not stopped accurately.

An important thing to consider is whether these errors yield qualitative or quantitative results, as this will determine how we interpret the data. In the case of quantitative results, an inaccurate measurement has a direct numerical impact on the outcome, whereas qualitative errors might inform the observational or descriptive aspects of the results.

To reduce experimental error, students could implement controls such as calibrating equipment before use, running multiple trials to find an average, and ensuring that all variables aside from the independent variable are kept constant. By discussing potential experimental errors and how they might be mitigated, students can better understand how to refine their experimental design for more accurate and reliable results.

The acceleration of the cart can be calculated using the equation a = (F - f) / m, where F is the applied force, f is the friction force, and m is the mass of the cart.

The acceleration of the cart can be expressed using Newton's second law, which states that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass.

Therefore, the acceleration (a) of the cart can be calculated using the equation:

a = (F - f) / m

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Answer:

Sirius A is 1.608 times the size of the Sun.

Explanation:

The radiant flux establishes how much energy an observer or a detector can get from a luminous source per unit time and per unit surface area.

[tex]R_{p} = \frac{L}{4\pi r^2}[/tex]  (1)

Where [tex]R_{p}[/tex] is the radiant power received from the source, L is its intrinsic luminosity and r is the distance.

The Stefan-Boltzmann law is defined as:

[tex]R_{p} = \sigma \cdot T^{4}[/tex]  (2)

Where [tex]R_{p}[/tex] is the radiant power, [tex]\sigma[/tex] is the Stefan-Boltzmann constant and T is the temperature.

Then, equation 2 can be replaced in equation 1

[tex]\sigma \cdot T^{4} = \frac{L}{4\pi r^2}[/tex] (3)

Notice that L is the energy emitted per second by the source.

Therefore, r can be isolated from equation 3.

[tex] r^2 = \frac{L}{4\pi \sigma\cdot T^{4}}[/tex]

[tex] r = \sqrt{\frac{L}{4\pi \sigma\cdot T^{4}}}[/tex]  (4)

The luminosity of the Sun can be estimated isolating L from equation 3.

[tex]L = (4\pi r^2)(\sigma \cdot T^{4}) [/tex]

but, [tex]r = 696.34x10^{6}m[/tex] and [tex]T = 5800K[/tex]

[tex]L_{Sun} = 4\pi (696.34x10^{6}m)^2(5.67x10^{-8} W/m^{2} K^{4} )(5800K)^{4}) [/tex]

[tex]L = 3.90x10^{26} W[/tex]

To find the luminosity of Sirius A, the following can be used:

[tex]\frac{L_{SiriusA}}{L_{sun}} = 23[/tex]

[tex]{L_{SiriusA}} = (3.90x10^{26} W)(23)[/tex]

[tex]{L_{SiriusA}} = 8.97x10^{27}W[/tex]

Finally, equation 4 can be used to determine the radius of Sirius A.

[tex] r = \sqrt{\frac{8.97x10^{27}W}{4\pi (5.67x10^{-8} W/m^{2} K^{4})(10000K)^{4}}}[/tex]

[tex]r = 1.12x10^{9}m[/tex]

So, Sirius A has a radius of [tex]1.12x10^{9}m[/tex]

[tex]\frac{1.12x10^{9}m}{696.34x10^{6}m} = 1608[/tex]

Hence, Sirius A is 1.608 times the size of the Sun.

Answer:

V = 0.5 m/s

Explanation:

Given,

Mass of the raft,M= 180 Kg

initial velocity of raft,u = 0 m/s

Final velocity of the raft,V = ?

Mass of swimmer 1, m₁ = 50 Kg

initial velocity of swimmer, u₁ = 0 m/s

Final velocity of the swimmer 1, v₁ = 3 m/s

Mass of swimmer 2, m₂ = 80 Kg

Initial velocity of the swimmer 2, u₂ = 0 m/s

Final velocity of the swimmer 2, v₂ = - 3 m/s

Using conservation of momentum

M u + m₁ u₁ + m₂ u₂ = M V + m₁ v₁ + m₂ v₂

M x 0 + m₁ x 0₁ + m₂x 0 = 180 x V + 50 x 3 + 80 x (-3)

180 V = 90

V = 0.5 m/s

Hence, the speed if the raft is 0.5 m/s in the direction of swimmer 1.

Answer:

P = 68.125 kW

P startup = 43.05 kW

Explanation:

The power  required to operate this ski lift is 43.05 KW.

The quantity of energy moved or converted per unit of time is known as power in physics. The watt, or one joule per second, is the unit of power in the International System of Units. A scalar quantity is power.

The lift is operating a a steady speed of 10 km/h = 10×(1000/3600) m/s = 25/9 m/s.

Average mass of the chair= 250 kg.

Acceleration of the chair = 25/9 /5 m/s² = 5/9 m/s².

Vertical component of this acceleration is = (5/9) ×{200/√(200²+1000²)} m/s²

= 0.1089 m/s²

Hence, the required height = 1/2 ×  0.1089 ×5² m = 1.362 m.

So, the total work done = mgh +1/2mv²

= 250×9.8×1.362 + 1/2× 250 × (25/9)² joule

= 215240.56 joule

So, the power  required to operate this ski lift =  215240.56 /5 watt = 43048.112 W = 43.05 KW.

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Answer:

A very massive main- sequence star

Explanation:

Degeneracy pressure refers to pressure expend by dense material , which is composed of fermions, which is an example of electrons in a white dwarf star. According to Pauli exclusion principle, which states that no two fermions can exist in the same quantum state, actually give details about the pressure.

When there is stellar masses that is less than about 1.44 of that of solar masses, there will be gravitational fall in the energy , and the energy will not be sufficient to produce the neutrons of a neutron star, therefore, the fall is abstruptly stopped through the electron degeneracy to form white dwarfs.this result to the creation of an effective pressure that further prevents gravitational fall.

Answer:

1 or 2 or 3

Explanation:

it depends whether the coat is a light or dark colour. if it is lighly coloured it will not absorb heat from the sun and wont melt the snowman. if it is darkly coloured it will be number 1

the coat wont make a difference if the temperature of the snowman is the same and the temperature outside the snoman and the sun isnt shining. the coat would just make him look smart - so number 2

it coul keep in the cold and block out the warmth so number 3

Answer:

8 ampere

Explanation:

P= V x I

so

I = P/V

I= 24 /3

I = 8 A

Answer:

Explanation:

What happens when a flame is deprived of oxygen? Carbon dioxide molecules are heavier than air. Because of this, they push the oxygen and other molecules in the air out of the way as they sink down over the flame and candle. When oxygen is pushed away from the wick, it can't react with the wax anymore. This makes the flame go out.

So if the flame is exposed to air, the flame will rise.

Answer: When gas is exposed to a small flame it explodes into a firerer blow torch at an unbelievable temperature of almost 450 degrees ^F

Explanation: This is just like igniting a lighter then placing an aerosol can of

fumeable gas then spraying the flammeable gas from the aerosol can into the flame of the lighter which will then give you a flamethrower.

A. True

According to the Faraday-Lenz law, the current in the rotor is generated by the change in the magnetic flux due to the rotating stator, the polarity of the induced current is such that it produces a magnetic field that opposes the change in magnetic flux that produced it. Which causes the rotor to turn

Answer:

Mostly absorbed and transmitted toward Earth's surface

Explanation:

Infrared radiation from the sun reaches the Earth's surface and warms the Earth's surface. It emits some infrared radiation, some absorbed by gases such as carbon dioxide in the atmosphere. This is known as the greenhouse effect. and If it don't, radiation from the earth is powerful enough to burn the skin.

so correct answer is Mostly absorbed and transmitted toward Earth's surface

Answer:

mostly absorbed and transmitted toward Earth's surface

Explanation:

Answer:

what is happiness

Explanation:

Answer:

Love is the answer to the question of how do you make someone do something that is not to their benefit. How do we stop bad people from doing bad things? How do we overcome greed? How can we find happiness if we always know that we have a limited time on earth?

Explanation: