Answer:
the correct answer is A
Explanation:
This is a doppler effect exercise which is the change in frequency due to the relative movement of the sound source and the observer.
[tex]f' = f_o \ \frac{v+v_o}{v-v_s}[/tex]
where v₀ is the speed of the observer and v_s the speed of the source, the signs correspond when the two are closing in
with this expression let's analyze the different answers
A) True. The observed change is in the frequency, in this case the two are moving away, so the expression that describes the phenomenon is
[tex]f'= f_o \ \frac {v-v_o}{ v+v_s}[/tex]
In this case, the speed of the source is greater than the speed of the observer, so when the denominator increases faster than the numerator, consequently the frequency must decrease
B) False. The amplitude does not depend on the relative velocity
C) False. The intensity depends on the distance, by or which when increasing the distance the intensity should decrease
D) False. The speed of sound is a constant, if the frequency decreases the wavelength must increase to maintain equality
E) False. The speed of sound depends on the properties of the propagating medium, not on the relative speed of the source and the observer.
Consequently the correct answer is A
Types of RM radiation that make up the electromagnetic spectrum are microwaves, infrared light, ultraviolet light, X-rays, and gamma rays.
True
False
Answer:
True
Explanation:
The electromagnetic spectrum can be regarded as term that give description of range of light that are in existence, and this range from radio waves up to gamma rays. It can be explained as
range of frequencies that electromagnetic radiation takes with thier respective wavelengths as well as photon energies
The Types of electromagnetic radiation that make up the electromagnetic spectrum are
✓ microwaves
✓ infrared light
✓ ultraviolet light
✓X-rays,
✓gamma rays.
A small wooden block with mass 0.750 kg is suspended from the lower end of a light cord that is 1.40 m long. The block is initially at rest. A bullet with mass 0.0100 kg is fired at the block with a horizontal velocity v0. The bullet strikes the block and becomes embedded in it. After the collision the combined object swings on the end of the cord. When the block has risen a vertical height of 0.800 m, the tension in the cord is 5.00 N.
Required:
What was the initial speed v0 of the bullet?
Answer:
The initial speed of the bullet will be:
[tex]v_{ib}=331.36\: m/s[/tex]
Explanation:
Using the momentum conservation:
[tex]p_{i}=p_{f}[/tex]
[tex]m_{b}v_{ib}=Mv[/tex] (1)
Where:
M is the mass of the black plus the mass of the bulletv(ib) is the initial velocity of the bulletv is the velocity of the block with the bullet inside.Using the conservation of energy:
[tex]\frac{1}{2}Mv^{2}=\frac{1}{2}Mv_{2}^{2}+Mgh [/tex] (2)
Where v(2) is the speed of the system at 0.8 m of vertical height.
Using the forces acting on the system we can find v(2).
The forces can be equal to the centripetal force:
[tex]T-Mg*sin(\alpha)=M\frac{v_{2}^{2}}{L}[/tex]
α is the angle of T with respect to the horizontal, here α = 25.4°
So, v(2) will be:
[tex]T-Mg*sin(\alpha)=M\frac{v_{2}^{2}}{L}[/tex]
[tex]\frac{L}{M}(T-Mg*sin(\alpha))=v_{2}^{2}[/tex]
[tex]\frac{1.4}{0.76}(5-0.76*9.81*sin(25.4))=v_{2}^{2}[/tex]
[tex]v_{2}=1.82 \: m/s[/tex]
Using this value on equation (2) we will find v.
[tex]v^{2}=v_{2}^{2}+2gh [/tex]
[tex]v^{2}=1.82^{2}+2(9.81)(0.8) [/tex]
[tex]v=4.36\: m/s [/tex]
And finally using equation (1) we can find the initial speed of the bullet.
[tex]m_{b}v_{ib}=Mv[/tex]
[tex]0.01*v_{ib}=0.76*4.36[/tex]
[tex]v_{ib}=331.36\: m/s[/tex]
I hope it helps you!
Radio waves travel at the speed of light. What is the wavelength of a radio signal with a frequency of 9.45 x 10^7 Hz?
The wavelength of this radio signal is equal to 3.18 meters.
Given the following data:
Frequency = [tex]9.45 \times10^7[/tex] Hz.Speed of light = [tex]3 \times 10^8[/tex] m/s.What is wavelength?Wavelength can be defined as the distance between two (2) successive crests (troughs) of a wave.
How to calculate wavelength.Mathematically, the wavelength of a wave is given by this formula:
[tex]\lambda = \frac{V}{F}[/tex]
Where:
F is the frequency of a wave.V is the speed of a sound wave.[tex]\lambda[/tex] is the wavelength of a sound wave.Substituting the given parameters into the formula, we have;
[tex]\lambda = \frac{3 \times 10^8}{9.45 \times10^7}[/tex]
Wavelength = 3.18 meters.
Find more information on waves here: brainly.com/question/23460034
The wavelength of the radio signal travel at speed of light is 3.17m.
Given the data in the question;
Frequency of the radio wave; [tex]f = 9.45 * 10^{7}Hz = 9.45 * 10^{7} s^{-1}[/tex]Wavelength of a radio signal; [tex]\lambda = \ ?[/tex]WavelengthWavelength the spatial period of a periodic wave. That is to say, when the shapes of waves are Wavelength , the distance over which they are repeated is called wavelength. Wavelength is expressed as;
[tex]\lambda = \frac{v}{f}[/tex]
Where [tex]\lambda[/tex] is wavelength, f is the frequency of the wave and c is the velocity or speed of light ( [tex]c = 3*10^8m/s[/tex] )
We substitute our values into the expression above.
[tex]\lambda = \frac{c}{ f}\\ \\\lambda = \frac{3*10^8m/s}{9.45*10^7s^{-1}} \\\\\lambda = \frac{3*10^8ms/s}{9.45*10^7}\\\\\lambda = 3.17m[/tex]
Therefore, the wavelength of the radio signal travel at speed of light is 3.17m.
Learn more about wavelength: brainly.com/question/16776907
My best friend just returned from the clinic. She just found out she is HIV- positive. She invited me for dinner. What should I do? Should I go? What do I say to her and her family? Can I eat the foods she cooked or touched? Will she be all right? Imagine this letter is from a friend. Write a page response. Include reasons for your advice.
Answer:
yes, because you dont want to be mean and make her feel worse about it and hiv has something do with s3x not germs so yes go
Explanation:
If a gas turned into a solid without going through the liquid state and how do you reverse it?
Answer:
put it in a volcano
Explanation:
What is the specific heat of a substance that absorbs 1600 joules of heat when a sample
of 18 g of the substance increases in temperature from 20 °C to 31°C? Round your answer
to two decimal places if necessary.
Answer:
8.08 J/g °C
Explanation:
Q=m*Cp*ΔT-->
Cp=Q/(m*ΔT) -->
Cp=1600/[18*(31-20)]-->
Cp=8.08 J/g °C
PLEASE HELP ME WITH THIS ONE QUESTION
A converging lens has a focal length of 40 cm. If an object is placed 50 cm in front of the image, where will the image be formed?
Answer:
the image will be real and inverted
HELP ME PLEASE <333, NUMBER 3 ONLY!
Answer:
b
Explanation:
is correct .....................
i think
. A circular wire loop 40 cm in diameter has 100 Ohm resistance and lies in a horizontal plane. A uniform magnetic field points vertically downward, and in 25 ms it increases from 5 mT to 55 mT. Find the magnetic flux through the loop at (a) the beginning and (b) the end of 25 ms period. (c) What is the loop current during this time
Answer:
(a) 6.283 Wb (b) 69.11 Wb (c) I = 0.628 A
Explanation:
Given that,
The diameter of the loop, d = 40 cm
Radius, r = 20 cm
Initial magnetic field, B = 5 mT
Final magnetic field, B' = 55 mT
Initial magnetic flux,
[tex]\phi_i=BA\\\\=5\times 10^{-3}\times \pi \times 20^2\\\\=6.283\ Wb[/tex]
Final magnetic flux,
[tex]\phi_f=B'A\\\\=55\times 10^{-3}\times \pi \times 20^2\\\\=69.11\ Wb[/tex]
Due to change in magnetic field an emf will be generated in the loop. It is given by :
[tex]\epsilon=-\dfrac{d\phi}{dt}\\\\=\phi_f-\phi_i\\\\=69.11-6.283\\\\=62.827\ V[/tex]
Let I be the current in the loop. We can find it using Ohm's law such that,
[tex]\epsilon=IR\\\\I=\dfrac{\epsilon}{R}\\\\I=\dfrac{62.827}{100}\\\\=0.628\ A[/tex]
Hence, this is the required solution.
What is another example of convection
Answer:
boiling water - When water heats, the heat from the burner is transferred to the container, heating the water at the bottom. This hot water rises, creating a circular motion, as colder water descends to replace it.
Question /
Which object is shown below?
A. Convex mirror
B. Convex lens
C. Concave lens
D. Concave mirror
SLIDNAT
o reduce the drag coefficient and thus to improve the fuel efficiency, the frontal area of a car is to be reduced. Determine the amount of fuel and money saved per year as a result of reducing the frontal area from 18 to 14 ft2. Assume the car is driven 12,000 mi a year at an average speed of 55 mi/h. Take the density and price of gasoline to be 50 lbm/ft3 and $3.10/gal, respectively; the density of air to be 0.075 lbm/ft3, the heating value of gasoline to be 20,000 Btu/lbm; and the overall efficiency of the engine to be 30 percent. Take the drag coefficient as CD
Complete question
To reduce the drag coefficient and thus to improve the fuel efficiency, the frontal area of a car is to be reduced. Determine the amount of fuel and money saved per year as a result of reducing the frontal area from 18 to 14 ft2. Assume the car is driven 12,000 mi a year at an average speed of 55 mi/h. Take the density and price of gasoline to be 50 lbm/ft3 and $3.10/gal, respectively; the density of air to be 0.075 lbm/ft3, the heating value of gasoline to be 20,000 Btu/lbm; and the overall efficiency of the engine to be 30 percent. Take the drag coefficient as CD=0.3 for a passenger car.
Answer:
22.22%
$57
Explanation:
From the question we are told that
Initial area of frontal area [tex]a_1=18ft^2[/tex]
Final area of frontal area [tex]a_2=14ft^2[/tex]
Distance covered a year [tex]D=12000mile[/tex]
Average speed a year [tex]V_{avg}=55mile/h[/tex]
Density [tex]\rho=50 lbm/ft3[/tex]
Price [tex]P= $3.10/gal[/tex]
Density of air [tex]\rho_{air} 0.075 lbm/ft3[/tex]
Heating value of gasoline [tex]Q=20,000 Btu/lbm[/tex]
Efficiency [tex]\eta=30\%[/tex]
Drag coefficient [tex]CD=0.3[/tex]
[tex]\triangle A=18-14ft^2=4ft^2[/tex]
Generally the equation for drag force [tex]C_D[/tex] is mathematically given as
[tex]F_D=\frac{C_DAPV^2}{2}[/tex]
[tex]F_D=\frac{0.3*18*0.075*(80.685^2)*A}{2}[/tex]
[tex]F_D=73.24Alb[/tex]
where [tex]v=55mil/h*1.467=80.685ft/s[/tex]
Generally the equation for work done W is mathematically given as[tex]W=F_D*L[/tex]
where [tex]L=12000mile*5280[/tex]
[tex]L=63360000[/tex]
[tex]W=73.24A*63360000[/tex]
[tex]W=4.6*10^9A[/tex]
Generally the equation for overall efficiency [tex]\eta[/tex] is mathematically given as
where
[tex]W_{req}=required\ gasoline\ power\ efficiency[/tex]
[tex]\eta=\frac{W}{W_{req}}[/tex]
[tex]W_{req}=\frac{W}{\eta}[/tex]
[tex]W_{req}=\frac{4.6*10^9}{0.3}[/tex]
[tex]W_{req}=1.55*10^{10}A[/tex]
Generally the equation for reduction fee with change in frontal area [tex]\triangle M[/tex] is mathematically given as
[tex]\triangle M =\triangle Vgasoline*cost[/tex]
Where
[tex]\triangle Vgasoline= volume\ reduction\ of\ gasoline[/tex]
[tex]\triangle Vgasoline=\frac{E_{req}}{H*P}[/tex]
[tex]\triangle Vgasoline=\frac{1.55*10^{10}A}{20000*778.169*32.2*50}[/tex]
if
[tex]20000btu/ibm=20000*778.169*32.2(1bm.ft^2/s)[/tex]
[tex]\triangle Vgasoline=\frac{1.55*10^{10}A}{20000*778.169*32.2*50}[/tex]
[tex]\triangle Vgasoline=0.61859A[/tex]
Therefore
[tex]\triangle M =0.61859A*3.10[/tex]
if [tex]1ft^2=7.48gal[/tex]
[tex]\triangle M =0.61859(4)*3.10*7.48[/tex]
[tex]\triangle M = \$ 57.671[/tex]
Generally the equation for reduction of fuel [tex]F_r[/tex]is mathematically given as
[tex]F_r=\frac{\triangle A}{\triangle i}*100[/tex]
where
[tex]\triangle i=18ft^2[/tex]
[tex]F_r=\frac{4}{18}*100[/tex]
Fuel reduction price by reducing front area is 22.22%
Money saved per year is $57
⦁ A certain resistor is required to dissipate 0.25 W, what standard rating should be used?
Answer:A
Explanation:
large roll of fabric
Costume Rendering
Scissors
Pattern
Bolt
Answer:
Do we have to choose out of those three?
Explanation:
A ray of laser light strikes a glass surface at an angle a=25.0° tot he normal and it is refracted to an angle b=18.5° to the normal. What is the index of refraction nb for this type of glass? Na=1.00
A. 3.26
B. 3.52
C. 1.32
D. 1.89
Answer:
1.33
Explanation:
According to snell's law,
n = sin(a)/sin(b)
Given
a = 25.0°
b = 18.5°
Substitute
n = sin25/sin18.5
n = 0.4226/0.3173
n = 1.33
Hence the index of refraction nb for this type of glass is 1.33
Imagine that the satellite described in the problem introduction is used to transmit television signals. You have a satellite TV reciever consisting of a circular dish of radius RRR which focuses the electromagnetic energy incident from the satellite onto a receiver which has a surface area of 5 cm2cm2. How large does the radius RRR of the dish have to be to achieve an electric field vector amplitude of 0.1 mV/mmV/m at the receiver
Answer:
R₁ = 0.126 m
Explanation:
Let's use the definition of intensity which is the power per unit area
I = P / A
the generated power is constant
P = I A
power is
P = E / t
if we perform the calculations for a given time, the wave energy is
E = q V
we substitute
P = [tex]\frac{q V\ A}{t}[/tex]
we can write this equation for two points, point 1 the antenna and point 2 the receiver
V₁A₁ = V₂A₂
A₁ = [tex]\frac{V_2}{V_1} \ A_2[/tex]
A₁ = 0.1 10⁻³ 5 10⁻⁴ /V₁
A₁ = 5 10⁻⁸ /V₁
In general, the electric field on the antenna is very small on the order of micro volts, suppose V₁ = 1 10⁻⁶ V
let's calculate
A₁ = 5 10⁻⁸ / 1 10⁻⁶
A₁ = 5 10⁻² m²
the area of a circle is
A = π r²
we substitute
π R1₁²= 5 10⁻²
R₁ = [tex]\sqrt{ \frac{5 \ 10^{-2} }{\pi } }}[/tex]
R₁ = 0.126 m
Calculate the force of an object that has a mass of 10kg and an acceleration of 4m/s²
A-40N
B-8N
C-2.5N
D-0.4N
An electron moves through a region of crossed electric and magnetic fields. The electric field E = 3059 V/m and is directed straight down. The magnetic field B = 1.14 T and is directed to the left. For what velocity v of the electron into the paper will the electric force exactly cancel the magnetic force?
Answer:
v = 2683.33 m/s
Explanation:
The magnetic force and the electric force on the electron must be the same, in order for them to cancel each other:
[tex]Electric\ Force = Magnetic\ Force\\Eq = qvBSin\theta \\\\v = \frac{E}{BSin\theta}[/tex]
where,
v = velcoity of electron = ?
E = Electric Field = 3059 V/m
B = Magnetic Field = 1.14 T
θ = Angle between velocity and magnetic field = 90°
Therefore,
[tex]v = \frac{3059\ V/m}{(1.14\ T)Sin90^o}[/tex]
v = 2683.33 m/s
The Image shows a magnetic field around the poles of a magnet. Identify the areas where the magnetic force is the strongest.
N
Answer:
strongest are at the points of the north pole and the south pole, specifically between the red box and the letter of each pole.
Explanation:
The lines of magnetic force are drawn so that the density of lines is proportional to the intensity of the magnetic field.
Therefore, the sections where the magnetic field is strongest are at the points of the north pole and the south pole, specifically between the red box and the letter of each pole.
What does the outer part of the disk turn into?
1) Planets and Moons
2) Interstellar Cloud
3) Planetary Nebula
4) It gets sucked into the star
Answer:
what does the outer part of the disk turn into
Explanation:
4) it gets sucked into the star
list some application of atmospheric pressure?
Answer:
Drinking straw, syringe, Dropper, vacuum, etc.
Explanation:
Aliens from the planet Mars can have long or short antennas. The allele for a long antenna is DOMINANT, and the allele for a short antenna is RECESSIVE. Which of the following is the pair of alleles an alien would have to inherit to have a short antenna?
Recessive, dominant
Dominant, dominant
Recessive, recessive
Dominant, recessive
Answer:
Recessive, dominant
Explanation:
umm thats the answer
Why did the “yielders” conform in Asch’s experiment?
Answer:
Asch's experiment showed that about 75% of people were "yielders" who conformed and 25% were "independent" who didn't conform. Asch concludes that people ignored reality and gave an incorrect answer in order to follow the rest of the group.
I WILL REPORT YOU IF YOU ANSWER WITH LINK!!! WILL GIVE BRAINLIEST
You have two identical bowling balls that are 1.00 m apart as measured from their centers. There is an attractive force of gravity between them due to their mass. When a net charge of +0.40 nC is placed on each bowling ball, the force exerted by the electrostatic forces exactly balances the force of gravity on the bowling balls resulting in a net charge of zero. The formula for the electrostatic force is similar to the formula for the gravitational force. There is a constant that is multiplied by the magnitude of each of the two charges and divided by the square of the distance between them. What two conclusions can you draw from this information?
CHOOSE 2 ANSWERS
Answer:
I think is is
Explanation:
B and C why because i have a gut feeling
So the the greater the height, the
farther something can fall, the greater
the potential energy.
True
False
A particle of ink in a ink-jet printer carries a charge of -8x 10^-13 C and is deflected onto paper force of 3.2x10^-4. Find the strength of the electric field
example of kinetic energy into heat energy
Answer:
The kinetic energy of large objects can be converted into this thermal energy.
Explanation:
For example, if you drop a water balloon onto the ground, its kinetic energy is converted mostly to thermal energy. If the balloon weighs 1 kilogram and you drop it from about 2 meters, it will heat up by less.
5. During a heat transfer investigation, students filled two cups with water. One cup contains 100mL of cold water while the other contains 100 mL of hot water.
A metal heat wire is placed inside the water of both cups and thermometers are attached to each cup. Which of the following BEST explains how the heat is transferred? Cold Water Hot Water.
A. This investigation would not result in any heat being transferred.
B. Convection, because the metal wire was heated through convection currents.
C. Radiation, because the metal wire was heated by electromagnetic waves.
D. Conduction, because the metal wire was in direct contact with water in both containers.
Answer:
D.Conduction, because the metal wire was in direct contact with water in both containers
Conduction, because the metal wire was in direct contact with water in both containers. Option D is correct.
Given that,
Students filled two cups with water. One cup contains 100mL of cold water while the other has 100 mL of hot water. A metal heat wire is placed inside the water of both cups and thermometers are attached to each cup.
It is to be identified, the system contains which type of heat transfer between the cups
Heat transfer is the process, in a thermodynamic system, when an object at a higher temperature is placed with an object at has a lower temperature, after some time the system attains equilibrium because heat flows from higher temperature to lower temperature.
In the given question,
Cups, that are connected through a metal wire, one is hot and the other is cold, Principal of conduction state that when there is a system of connected bodies the heat flows throughout the connected system till the thermal equilibrium attain. Implies heat flow from hot cup to cold cup through the wire through conduction heat transfer.
Thus, Conduction, because the metal wire was in direct contact with water in both containers. Option D is correct.
Learn more about heat transfer here:
https://brainly.com/question/20699475
#SPJ2
Which of the following is the most important difference between a permanent magnet and a electromagnet
Answer:
Explanation: the major difference between an electromagnet and permanent magnet is that the former can have a magnetic field when electric current flows through it and disappears when the flow of the current stops. ... It will always displays the magnetic behaviour.
HELP!!!!
A student did an experiment to determine the
specific heat capacity of an unknown metal.
She heated 1.00 x 10- kg of the metal to 225°C
and quickly placed it in an insulated container
(negligible specific heat capacity) that contained
0.0900 kg of water at a temperature of 18.0°C.
What is the final temperature of the water if the
specific heat capacity of the metal is
2.11 x 102 J/kg.°C?
Answer:
T₂ = 16.83°C
Explanation:
Applying the law of conservation of energy principle here in this situation we get the following equation:
[tex]Energy\ Lost\ by\ Metal = Energy\ Gaine\ by\ Water\\m_{metal}C_{metal}(T_2-T_{1metal}) = m_{w}C_{w}(T_2-T_{1w})[/tex]
where,
T₂ = Final Temperature of Water = Final Temperature of Metal = ?
C_metal = Specififc Heat Capacity of the metal = 2.11 x 10² J/lg.°C
T_1metal = Initial Temperature of Metal = 225°C
m_metal = mass of metal = 1 x 10⁻²[tex](0.01\ kg)(211\ J/kg.^oC)(T_2-225^oC) = (0.09\ kg)(4184\ J/kg.^oC)(T_2-18^oC)\\2.11 T_2 - 474.75 = 376.56T_2 - 6778.08\\374.45T_2 = 6303.33\\[/tex] kg (exponent assumed due to missing info in question)
C_w = Specififc Heat Capacity of the water = 4184 J/lg.°C
T_1w = Initial Temperature of water = 18°C
m_w = mass of water = 0.09 kg
Therefore,
[tex](0.01\ kg)(211\ J/kg.^oC)(T_2-225^oC)=(0.09\ kg)(4184\ J/kg.^oC)(T_2-18^oC)\\\\2.11 - 474.75T_2 = 376.56 - 6778.08T_2\\[/tex]
T₂ = 16.83°C