Answers
The correct statement explaining how a megaphone amplifies sound is: "A megaphone amplifies sound by focusing sound energy into one specific direction."
How does a loudhailer increase sound volume?By increasing the acoustic impedance perceived by the vocal chords and bringing them into closer proximity to the air, the loudhailer amplifies the sound and increases the amount of sound power that is emitted.
What kind of sound does a loudhailer produce?Many people are familiar with the distinctively distorted sound of a human voice amplified by a loudhailer thanks to its use in train and bus stations and sporting venues. It produces the sound of a vintage acoustic phonograph record player when used with music.
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Related Questions
Four point masses 2kg, 4kg, 6kg and 8kg are placed at the corners of Square ABCD of 2cm long respectively. Find the Position of centre of mass of the system from the corner A.
please help me I give you 50 coins
Answers
Let's call the mass at point A M1, the mass at point B M2, the mass at point C M3, and the mass at point D M4.
The x-coordinate of the center of mass is given by:
x_cm = (M1*x1 + M2*x2 + M3*x3 + M4*x4) / (M1 + M2 + M3 + M4)
The y-coordinate of the center of mass is given by:
y_cm = (M1*y1 + M2*y2 + M3*y3 + M4*y4) / (M1 + M2 + M3 + M4)
We know that the distance between any two adjacent corners of the square is 2cm. Therefore, we can say that the coordinates of the four masses are:
M1 = 2kg at (0,0)
M2 = 4kg at (2,0)
M3 = 6kg at (2,2)
M4 = 8kg at (0,2)
Substituting these values into the equations above, we get:
x_cm = (2*0 + 4*2 + 6*2 + 8*0) / (2 + 4 + 6 + 8) = 2
y_cm = (2*0 + 4*0 + 6*2 + 8*2) / (2 + 4 + 6 + 8) = 2
Therefore, the center of mass of the system is located at a distance of 2cm from corner A along the x-axis and 2cm from corner A along the y-axis.
6.1 Instantaneous communication. In your own words, explain why you
cannot send a message instantaneously using the mechanism of ex-
periment 6.1. If quantum mechanics were deterministic rather than
probabilistic, yet the distant atoms still always left from opposite
exits of a stern gerlach analyzer, would you then be able to send a message instantaneously?
What if the operator of the left-hand Stern-Gerlach analyzer were
somehow able to force his atom to come out of the + exit?
Answers
We can see here in one's own words, instantaneous communication would still not be conceivable even if quantum mechanics were predictable and the results of measurements could be predicted in advance. This is because, even if they were entangled, any attempt to change the state of one atom would inevitably change the state of the other atom.
What is quantum mechanics?The behavior and interaction of particles at the atomic and subatomic scales is the subject of quantum mechanics, a subfield of physics. It offers a mathematical framework for describing the probabilistic nature of physical occurrences in the microscopic world as well as the wave-particle duality of matter.
Until they are measured or observed, particles in quantum mechanics do not have fixed positions or attributes, and the measurement process might have an impact on the system being examined.
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The Titanic had a mass of 52,800 tonnes and was travelling at 41.74 km/h when
the iceberg was sighted. By the time it hit the iceberg 30 seconds later, it had
slowed to 38.5 km/h
What was the force?
Answers
Answer:
Explanation:
mv^2/2/t=712,2kN
Help. Don’t mind the highlighter answers i don’t know if there right
Answers
A convex lens is also known as a converging lens because it causes the incident light rays that are travelling parallel to its main axis to converge.
A convex lens has an outward curvature. In comparison to the edges, the middle is thicker. The rays of light bend in the direction of one another when they travel through a convex lens. On the other side of the lens, the rays only come together at one location. Convex lenses amplify or provide the impression that objects are larger.
The image is upside down in relation to the original object and is also oriented inverted from right to left in the convex lens. The term "inverted" refers to such a position. The real image formed by the convex lens is inverted.
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During an ultrasound, sound waves are sent by a transducer through muscle tissue at a speed of 1,300 m/s. Some of the sound waves are reflected from a metal fragment 5.0 cm into the muscle tissue. How long did it take the transducer to detect the reflected waves from the metal fragment after they were first emitted?
0.26 seconds
39 seconds
4.6 E−5 seconds
7.7E−5 seconds
Answers
time = distance / speed
where distance is the round-trip distance traveled by the sound waves (i.e., twice the distance from the transducer to the metal fragment) and speed is the speed of sound in muscle tissue.
The round-trip distance traveled by the sound waves is:
2 * 5.0 cm = 10.0 cm = 0.1 m
The speed of sound in muscle tissue is given as 1,300 m/s.
Therefore, the time it took for the reflected waves to be detected is:
time = distance / speed = 0.1 m / 1,300 m/s = 7.7E−5 seconds
So the answer is 7.7E−5 seconds (option D).
(d) 7.7E−5 seconds
To calculate the time it takes for the reflected waves to return to the transducer, we can use the formula:
time = distance / speed
The distance the sound waves travel is twice the depth of the metal fragment, since they have to travel to the fragment and then back to the transducer. Therefore, the distance traveled by the sound waves is:
distance = 2 x 5.0 cm = 0.1 m
The speed of the sound waves in muscle tissue is 1,300 m/s. Therefore, the time taken for the waves to travel this distance is:
time = distance / speed = 0.1 m / 1,300 m/s = 7.7E−5 seconds
Therefore, the transducer takes 7.7E−5 seconds to detect the reflected waves from the metal fragment after they were first emitted.
The correct answer is (d) 7.7E−5 seconds.
An object vibrates with a frequency of 2200 Hz to produce sound waves that travel through air with a speed of 340 m/s. Adjacent compressions (i.e., wavelengths) in the sound wave are a distance of meters apart.
Answers
The adjacent compressions in the sound wave are 0.155 meters apart.
This distance is also known as the wavelength of the wave. We are given the frequency of the vibration and the speed of sound in air. The formula for wavelength is:
wavelength (λ) = speed of sound (v) / frequency (f)
We are given the frequency of the sound wave as 2200 Hz and the speed of sound through air as 340 m/s.
Plugging these values into the formula gives:
λ = 340 m/s / 2200 Hz = 0.155 meters
Therefore, adjacent compressions (i.e., wavelengths) in the sound wave are a distance of 0.155 meters apart.
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3. You may have seen this question previously but now you will approach it using energy
concepts.
A pair of sleds weighs 25 kg and experience a frictional force of 25 N. If a dog team applies a
175 N force pulling it 12 m find:
a) the work done by friction.
b) the work done by the dog team.
c) the net work done (using the net force). How does then net work compare to the answers
from the previous two parts of the question?
d) What form of energy does the frictional force represent? What form of energy does the net
force produce?
Answers
a) Work done by friction is 300 J.
b) Work done by the dog team is 2100 J
c) Net work done 1800 J.
d) loss of mechanical energy.
How to determine work done?a) The work done by friction can be calculated using the formula
W = Fd, where F = frictional force and d = distance moved.
Therefore, W = 25 N × 12 m = 300 J.
b) The work done by the dog team can be calculated using the same formula, where F = force applied by the dog team.
Therefore, W = 175 N × 12 m = 2100 J.
c) The net work done is the sum of the work done by the dog team and the work done by friction.
Therefore, the net work done is
2100 J - 300 J = 1800 J.
The net work done is positive, which means that the sleds have gained energy.
d) The frictional force represents the loss of mechanical energy due to the interaction between the sleds and the ground. This energy is converted into thermal energy or heat. The net force produced by the dog team produces kinetic energy, which is the energy of motion of the sleds.
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Eight identical point charges of Q coul each are placed at the corners of a cube whose sides have a length of 10 cm.
α. Find the electric field at the center of the cube.
b. Find the electric field at the center of a face of the cube.
c. Find the field at the center of the cube if one of the corner charges is removed
Answers
The electric field at the center of the cube is approximately 5.12 × 10⁴ N/C.
The electric field at the center of a face of the cube is approximately 4.54 × 10⁴ N/C.
The electric field at the center of the cube if one of the corner charges is removed is approximately 4.54 × 10⁴ N/C.
(a) To find the electric field at the center of the cube, we can use the principle of superposition, which states that the total electric field at a point in space is the vector sum of the electric fields due to each individual charge. Since all eight charges are identical and have the same distance to the center of the cube, the electric field due to each charge has the same magnitude and direction.
Using Coulomb's law, we can calculate the magnitude of the electric field due to one charge at the center of the cube as:
E = (kQ) / r²
where k is the Coulomb constant, Q is the charge on each point charge, and r is the distance from the charge to the center of the cube. Since the charges are at the corners of a cube with sides of length 10 cm, the distance from each charge to the center is sqrt√/2 times the length of the side, or 5√(3) cm.
Thus, the magnitude of the electric field due to one charge at the center of the cube is:
E = (kQ) / (5√(3) cm)² = 1.24 × 10⁴ N/C
Since there are eight charges, the total electric field at the center of the cube is:
E_total = 8E = 9.95 × 10⁴ N/C
(b) To find the electric field at the center of a face of the cube, we can again use the principle of superposition. Since the face of the cube is equidistant from four of the charges, the electric field due to those charges has the same magnitude and direction, while the electric field due to the other four charges cancels out.
So, the magnitude of the electric field at the center of a face of the cube is:
E_face = 4E = 4.96 × 10⁴ N/C
(c) If one of the corner charges is removed, the electric field at the center of the cube is no longer spherically symmetric. However, we can still use the principle of superposition to calculate the electric field due to the remaining seven charges. The electric field due to these charges at the center of the cube has the same magnitude as the electric field due to one charge at the center of a face of the cube.
Since the distance from the center to each of the remaining charges is √(2) times the length of the side of the cube.
Thus, the magnitude of the electric field due to the remaining charges is:
E_remaining = 7E = 3.18 × 10⁴ N/C
Therefore, the electric field at the center of the cube if one of the corner charges is removed is approximately 4.54 × 10⁴ N/C, which is the average of the electric fields at the centers of adjacent faces of the cube.
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Q8 (10pts)
You are working with cartesian unit vectors and ŷ in the plane of the board. Your friend is introducing a
new unit vector  = 0.52 + qŷ, but isn't sure what value q should have. Solve for q and make a
recommendation for what value they could use. If you determine more than one possible value for g,
mention this in your recommendation.
Answers
The length one vectors i, j, and k, which stand for conventional measure vectors in three different dimensions, contribute along the positive x, y, and z axes, respectively.
What are the Cartesian plane's unit vectors?Unit vectors i and j, which run along the x-axis and y-axis, respectively, define the Cartesian coordinate system. The radial unit vector r, which indicates the direction away from the origin, and the unit vector t, which is orthogonal (perpendicular) to the radial direction, together create the polar coordinate system.
Can a unit vector be created by adding two unit vectors?The size of the discrepancy is three if the product of two vectors with units is a unit vector. steps to determine the size of Consider a and b, two unit vectors whose total is a unit vector c.
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HELP!!! You have two substances, both of which have the same boiling point (or attraction between their molecules).
The first substance is made from molecules that are small (just a few atoms bonded together), and the second substance is made from mol that are larger (many atoms bonded together).
How can it be possible for two such different molecules to yield substances with the same boiling point? Describe the kinds of intermolecu attractions that must be involved and any other properties of the molecules that could cause this result.
Answers
The boiling point of a substance depends on the strength of the intermolecular forces between its molecules. In the case of the two substances you mentioned, even though they have different molecular sizes, they can still have the same boiling point if they have similar intermolecular attractions.
What is the boiling point about?For example, the smaller molecule may have a higher polarity due to the presence of polar bonds, which can result in dipole-dipole interactions between molecules. The larger molecule may have a similar dipole moment even though it has more atoms, or it may have a polar functional group that contributes to its intermolecular interactions.
In addition to dipole-dipole interactions, the molecules may also have London dispersion forces, which are present in all molecules due to the random fluctuations in electron density. These forces are proportional to the size of the molecule, so the larger molecule may have a stronger dispersion force even if it is less polar than the smaller molecule.
Therefore,, it is possible for two different molecules to have the same boiling point if they have similar intermolecular attractions, such as dipole-dipole interactions and London dispersion forces. The size of the molecule may also play a role in determining the strength of these forces, but it is not the only factor.
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The current-potential difference graph for a resistor is a straight line as long as the is constant. What is the missing word?
Answers
Answer:
Potential Difference = Voltage = Resistance * Current
As long the resistance is a constant the PD will be a straight line when plotted against the current.
(•) How many electrins represent a Change of -70 mic?
Answers
The number of electrons represent a Change of -70 μC is 4.3 × 10¹⁴.
Electric charge is the physical property of matter that experiences force when it is placed in electric field. F = qE where q is amount of charge, E = electric field and F = is force experienced by the charge. there are two types of charges, positive charge and negative charge which are generally carried by proton and electron resp. like charges repel each other and unlike charges attract each other. the flow charges is called as current. Elementary charge is amount of charge a electron is having, whose value is 1.602 x 10⁻¹⁹ C
The value of elementary charge that is charge on 1 electron is 1.6× 10⁻¹⁹ C
-70 μC = N × 1.6× 10⁻¹⁹ C
N = -70 μC / 1.6× 10⁻¹⁹ C
N = -70 μC / 1.6× 10⁻¹⁹ C
N = 4.3 × 10¹⁴ electrons
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A ball of mass 200g falls freely under gravity from a height of 50m. find the time taken to fall through a distance of 30m. given that the acceleration due to gravity g = 10m/s^2.
Answers
The time taken by the ball to fall through a distance of 30m is, 2 seconds
To calculate the time taken to fall through a distance of 30m, we have given data as,
mass of ball = 200g
g = 10 m/s^2
Initial height = 50 meter
Final height = 30 meter
So by the laws of motion, we have,
Δh = (ut) + (at²/2)
where, (u = initial velocity), and (t = time)
So,
50-30 = (0.t) + [10 x t²)/2]
20 = 5t²
Therefore, t = ± (2 seconds)
On eliminating the negative value as time can`t be negative here, we get
t = 2 seconds
Therefore, the time taken by the ball to fall through a distance of 30m is, 2 seconds
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A rocket is fired from the earth to the moon at a speed of 0.930c. Let two events be "rocket leaves earth" and "rocket hits moon"
A. In the earth's reference frame, calculate Δx for these events.
B. In the earth's reference frame, calculate Δt for these events.
C. In the earth's reference frame, calculate the spacetime interval s for these events.
D. In the earth's reference frame, calculate Δx' for these events.
E. In the earth's reference frame, calculate Δt' for these events.
F. In the earth's reference frame, calculate the spacetime interval s' for these events.
G. In the earth's reference frame, calculate Δx if a rocket is replaced with a laser beam.
H. In the earth's reference frame, calculate Δt if a rocket is replaced with a laser beam.
I. In the earth's reference frame, calculate the spacetime interval s if a rocket is replaced with a laser beam.
Express ALL parts with appropriate units
Answers
A. Δx = 384,400 km (distance between Earth and Moon)
How to solveB. Δt = 384,400 km / (0.930 * 299,792 km/s) ≈ 1.421 s
C. s² ≈ (-2.781 * 10^10) km² (imaginary number, time-like separated events)
D, E, F. Cannot answer without specified primed frame.
G. Δx for laser beam = 384,400 km
H. Δt for laser beam = 384,400 km / 299,792 km/s ≈ 1.282 s
I. s² for laser beam ≈ 0 km² (light-like separated events)
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describe what the weather would be like as a warm front passes, then describe what would occur as a cold front passes.
Answers
The air becomes humid during warm front passes and a cold front means a transition where warm air is being replaced by the cold air.What do you mean by weather?
The weather means the atmosphere at a particular place and time with respect to temperature, pressure, cloudiness, wind, etc.
A warm front means when the air is very warm and humid as compared to before.
A cold front is when the air is very colder and drier than the air above it. More than 15 degrees temperature can drop down when a cold front passes.
A cold front will probably bring winds, thunderstorms, and rain.Therefore, the cold front moves faster than the warm front.Learn more about the Weather here:
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the laboratory for a body. I in rth. Total:[4] (2) bout a point? ...[1] hat are they? [2] le which is ntally by an (11 iform metre rule Figure 4.1 below shows astone of mass 2kg which drops from the top of a cliff and takes two seconds to strike the ground Acceleration of free fall.g=10m/s². Stone T 77 Figure 4.1 (a) Name the form of energy possessed by the stone before it falls. (b) Determine the height of the cliff (c) Calculate (i) Ground Height,h.......... [2] The kinetic energy of the stone when half way down. [1] Kinetic energy......... The final velocity of the stone as it strikes the [2] stone Klif
Answers
The stone possesses potential energy at the top of the cliff, which is converted to kinetic energy as it falls toward the ground. Using the formula for the distance traveled by a freely falling object, we can calculate that the height of the cliff is 20 meters. The ground height is equal to zero, and when the stone is halfway down, it has a kinetic energy of 100 Joules. Using the formula for the final velocity of a freely falling object, we can calculate that the stone's final velocity as it strikes the ground is 20 m/s.
(a) The form of energy possessed by the stone before it falls is potential energy. When the stone is at the top of the cliff, it has the potential to do work due to its position relative to the ground. This potential energy is converted into kinetic energy as the stone falls towards the ground.
(b) We can use the formula for the distance traveled by a freely falling object to determine the height of the cliff:
d = 1/2 * g * t^2
where d is the distance, g is the acceleration due to gravity, and t is the time taken to fall.
Substituting the given values, we get:
d = 1/2 * 10m/s^2 * (2s)^2
d = 20 meters
Therefore, the height of the cliff is 20 meters.
(c)
(i) The ground height h is equal to zero since it is the reference level.
(ii) When the stone is halfway down, it has fallen a distance of d/2 = 10 meters. At this point, all of the potential energy has been converted to kinetic energy. We can use the formula for kinetic energy to calculate the kinetic energy of the stone:
KE = 1/2 * m * v^2
where KE is the kinetic energy, m is the mass of the stone, and v is its velocity.
Substituting the given values, we get:
KE = 1/2 * 2kg * (2 * g * d/2)
KE = 100 Joules
Therefore, the kinetic energy of the stone when halfway down is 100 Joules.
(iii) To find the final velocity of the stone as it strikes the ground, we can use the formula for the final velocity of a freely falling object:
v = sqrt(2 * g * d)
where v is the final velocity, g is the acceleration due to gravity, and d is the distance fallen.
Substituting the given values, we get:
v = sqrt(2 * 10m/s^2 * 20m)
v = sqrt(400)
v = 20 m/s
Therefore, the final velocity of the stone as it strikes the ground is 20 m/s.
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Two small Styrofoam balls that are separated (between their centers) by 4 cm experience a force of attraction of 15 N. If the balls are separated by 8 cm, the force between them would be ___ N.
Answers
Answer:
f = 15/4 = 3.75
Explanation:
2. Review the chart above. What information about ultraviolet radiation supports or
contradicts the safety of solar radiation exposure to astronauts on the international
space station?
The table shows the amount of time astronauts spent on the surface of Moon during
Answers
The information about ultraviolet radiation supports or contradicts the safety of solar radiation exposure to astronauts on the international space station. They have wore suits that protects the astronaut from the UV light.
A space station is a sort of space habitat because it can sustain a human crew in orbit for a lengthy period of time. Major landing or propulsion systems are absent. An artificial satellite, also known as an orbital station or orbital space station, is a kind of orbital spaceflight. To allow other spacecraft to dock and transfer personnel and cargo, stations need to have docking ports. Depending on the programmed, a given orbiting outpost has a different role. Military launches have also taken place, although scientific launches of space stations have predominated. astronaut have wore suits that protects the astronaut from the UV light.
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What is the S-P difference (sec)?
What is the amplitude (mm)?
What is the distance (km)?
What is the magnitude (M)?
Answers
(a) The S-P difference (sec) is 40 sec.
(b) The amplitude (mm) is 10 mm
(c) The distance (km) is 380 km
(d) The magnitude (M) is 4.5
What is the S-P wave difference (sec)?
The S-P wave difference (sec) is a measure used in seismology to determine the distance between a seismic station and an earthquake source.
From the graph, the S-P difference, that is between S and P = 40 s - 0 s
= 40 s
The distance (km) corresponding to 40 sec is 380 km.
The amplitude of the wave is the maximum displacement of the wave and it is equal to 10 mm.
The corresponding magnitude of the wave is 4.5.
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Which step of the PRICES method is represented by the letter S?
A.
Raise the injured area above the heart.
B.
Stop the activity until the injury is evaluated.
C.
Wrap the injured site to decrease swelling.
D.
Apply a brace or a splint to the area.
Answers
Economics NCS Topic Test No 5. Perfect Market 1.3. Give ONE term for each of the following descriptions. Write uonly the term next to the question numbers (1.3.1 to 1.3.5) in the ANSWER BOOK. Abbreviations, acronyms and examples will NOT be accepted. 1.3.1 Actual expenditure of business such as wages and interest 1.3.2 The cost that changes as more or less outputs are produced 1.3.3 An institution that can make final decisions by reviewing the decisions of the competition commission and Tribunal. 1.3.4 A word that describe the characteristics of differentiated product in oligopoly or monopolistic competition. 1.3.5 A period when inputs or factors of production are fixed. (5x1) (5) TOTAL SECTION A: [201
Answers
1.3.1 - Operating costs
1.3.2 - Variable costs
1.3.3 - Competition Appeal Court
1.3.4 - Product differentiation
1.3.5 - Short run
4.
Large speaker cones produce deeper frequencies than small speaker cones.
O True
MacBook Air
False
Answers
The given statement that Large speaker cones produce deeper frequencies than small speaker cones is true.
What is the justification?The frequency response of a speaker refers to its ability to reproduce sound across different frequencies. In general, larger speaker cones are capable of moving more air and producing lower frequencies than smaller cones. This is because the size of the speaker cone affects the amount of air it can displace and the amount of force it can generate.
Low-frequency sounds require more movement of air to be heard, and larger cones are better suited to move the necessary amount of air. However, it's worth noting that there are other factors that can affect a speaker's frequency response, such as the design of the speaker cabinet, the materials used in the speaker cone, and the quality of the electronics used to power the speaker.
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A is a sphere that is traveling with velocity of (3,7)m/s and had a mass of 5 kg .it collide with sphere B and both particle move together with velocity of (1,4)m/s after the collision. Sphere B has a mass of 4 kg . Find the velocity of B before the collision
Answers
The velocity of sphere B is -1.475 m/s. Which is in opposite direction to the direction of sphere A.
What is velocity?Velocity is the rate of change of displacement.
To calculate the velocity of sphere B before collision, we use the formula below
Formula:
u = [V(M+m)-Mu']/m................... Equation 1Where:
u = Velocity of sphere B before collisionV = Velocity of both particles after collisionM = Mass of sphere Am = Mass of sphereu' = Velocity of sphere B before collisionFrom the question,
Given:
V = 1.4 m/sM = 5 kgm = 4 kgu' = 3.7 m/sSubstitute these values into equation 1
u = [1.4(5+4)-(5×3.7)]/4u = (12.6-18.5)/4u = -5.9/4u = -1.475Hence, the velocity of sphere B is -1.475 m/s.
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4-What is the equivalent resistance of this circuit?
( )32 Ω
( )43 Ω
( )48 Ω
( )74 Ω
Answers
Explanation:
The parallel resistors ( 10 and 40 Ω) have an equivalent resistance of
( 40 * 10 ) / ( 40 + 10 ) = 8 Ω
Then you can add all of the series resistances to find the total resistance
15 + 25 + 8 Ω = 48 Ω
Remember V = IR ....then V/R = I
Current = V/ R = 55 v / 48 Ω = 1.15 A
An engine using 1 mol of an ideal gas initially at 18.7 L and 370 K performs a cycle
consisting of four steps:
1) an isothermal expansion at 370 K from
18.7 L to 33 L ;
2) cooling at constant volume to 209 K ;
3) an isothermal compression to its original
volume of 18.7 L; and
4) heating at constant volume to its original
temperature of 370 K .
Find its efficiency. Assume that the
heat capacity is 21 J/K and the universal gas constant is 0.08206 L · atm/mol/K =
8.314 J/mol/K
Answers
1) Isothermal expansion: During this step, the gas expands from a volume of 18.7 L to 33 L at a constant temperature of 370 K. Since the process is isothermal, the gas obeys the ideal gas law:
PV = nRT
where P is the pressure, V is the volume, n is the number of moles, R is the universal gas constant, and T is the temperature.
The pressure of the gas during this step can be found by rearranging the ideal gas law:
P = nRT/V
Substituting the given values, we get:
P = (1 mol)(8.314 J/mol/K)(370 K)/(18.7 L) = 162.7 kPa
The work done during this step is given by:
W1 = -∫PdV
where the integral is taken from the initial volume of 18.7 L to the final volume of 33 L. Since the process is isothermal, the pressure can be substituted into the integral:
W1 = -nRT ln(Vf/Vi)
Substituting the given values, we get:
W1 = -(1 mol)(8.314 J/mol/K)(370 K) ln(33 L/18.7 L) = -8201 J
2) Cooling at constant volume: During this step, the gas is cooled from a temperature of 370 K to 209 K at a constant volume of 18.7 L. Since the volume is constant, no work is done during this step. The amount of heat removed from the gas is given by:
Q2 = nCΔT
where C is the heat capacity and ΔT is the change in temperature. Substituting the given values, we get:
Q2 = (1 mol)(21 J/K)(209 K - 370 K) = -3366 J
Note that the negative sign indicates that heat is being removed from the gas.
3) Isothermal compression: During this step, the gas is compressed back to its original volume of 18.7 L at a constant temperature of 209 K. Using the same approach as in step 1, we can find the pressure of the gas:
P = (1 mol)(8.314 J/mol/K)(209 K)/(18.7 L) = 93.0 kPa
The work done during this step is given by:
W3 = -nRT ln(Vi/Vf) = (1 mol)(8.314 J/mol/K)(209 K) ln(18.7 L/33 L) = 4082 J
Note that the negative sign indicates that work is being done on the gas.
4) Heating at constant volume: During this step, the gas is heated back to its original temperature of 370 K at a constant volume of 18.7 L. Again, no work is done during this step. The amount of heat added to the gas is given by:
Q4 = nCΔT = (1 mol)(21 J/K)(370 K - 209 K) = 3381 J
The net work done by the engine during the cycle is given by:
Wnet = W1 + W3 = -8201 J + 4082 J = -4120 J
The net heat supplied to the engine during the cycle is given by:
Qnet = Q2 + Q4 = -3366 J + 3381 J = 15 J
The efficiency of the engine is given by:
η = Wnet/Qnet = -4120 J/15 J = -275.3
Note that the negative sign indicates that the engine is not operating as a heat engine, but rather as a heat pump or refrigerator. This is because the amount of work done by the engine is greater than the amount of heat supplied to the engine, which violates the second law of thermodynamics.
from time 15 seconds to 32 s the path of a car is part of a circle. For this motion the state the direction of the resultant force on the car and what happens to the velocity of the car
Answers
Since the car is moving in a circular path, it is undergoing centripetal acceleration toward the center of the circle. This acceleration is caused by a net force directed towards the center of the circle, which is the resultant force on the car. This force is known as the centripetal force.
Centripetal force is the net force that acts on an object moving in a circular path, directed towards the center of the circle. This force is responsible for the object's centripetal acceleration and is necessary to keep the object moving in a circular path.
According to Newton's second law of motion, F=ma, where F is the net force, m is the mass of the object, and a is the acceleration of the object. Since the car is experiencing centripetal acceleration, which is perpendicular to its velocity, the direction of the net force is also perpendicular to the velocity.
As a result, the direction of the net force on the car is towards the center of the circle. If the net force were to suddenly disappear, the car would move off in a straight line tangent to the circle.
Therefore, Since the net force on the car is constantly changing the direction of the car's velocity, the velocity is also changing. Specifically, the velocity is changing in direction, but not in magnitude, since the car is moving at a constant speed along the circular path. This change in the direction of the velocity is what causes the acceleration, and therefore the centripetal force.
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The force
Answers
Answer: .
Explanation: .
a satellite revolves around the earth in an orbit of radius 42000000m. find the value of g and its orbital speed at this hieght.
Answers
Answer:
Step 1: Given data
Acceleration due to gravity on the surface of the earth is g.
The radius of the earth is R and x is the height of the satellite above the earth's surface.
The mass of the satellite is m.
Step 2: Calculate the orbital speed of the satellite.
We know that,
mv2R+x=GMmR+x2
v=GMR+x
v=GMR2×R2R+x
Step 3: Final answer
v=gR2R+x
We can also write it as
v=gR2R+x12
As clothing tumble in a dryer, they can become charged. If a small piece of lint with a charge of +1.62 E−19 C is attracted to the clothing by a force of 2.0 E−9 N, what is the magnitude of the electric field at this location?
0.38 E10 N/C
1.2 E10 N/C
3.2 E10 N/C
3.6 E10 N/C
Answers
Answer:
1.2 E10 N/C
Explanation:
The force between two charged objects can be calculated using Coulomb's law:
F = k * q1 * q2 / r^2
where F is the force, k is Coulomb's constant (k = 8.99 x 10^9 N m^2 / C^2), q1 and q2 are the charges of the two objects, and r is the distance between them.
Rearranging this equation to solve for the electric field at a point, we get:
E = F / q
where E is the electric field strength and q is the charge at that point.
Substituting the given values, we get:
E = (2.0 x 10^-9 N) / (1.62 x 10^-19 C)
E = 12345.68 N/C
Therefore, the magnitude of the electric field at this location is 1.235 x 10^4 N/C.
a) Two asteroids collide and stick together. The first asteroid has mass of 18 × 10^3 kg and is initially moving at 780 m/s. The second asteroid has mass of 23 × 10^3 kg and is moving at 1050 m/s. Their initial velocities made an angle of 15° with respect to each other. What is their final speed and direction with respect to the velocity of the first asteroid?
Answers
The final velocity's angle with regard to the first asteroid's velocity is the same as the angle of the first asteroid's beginning velocity, which is 15° with respect to the x-axis.
How to determine final speed and direction?To solve this problem, using the law of conservation of momentum, the two asteroids stick together, so consider them as a single system.
Let's start by finding the initial momentum of the system:
p₁i = m₁v₁i = (18 × 10³ kg)(780 m/s) = 1.404 × 10⁷ kg⋅m/s
p₂i = m₂v₂i = (23 × 10³ kg)(1050 m/s) = 2.415 × 10⁷ kg⋅m/s
The initial momentum of the system is the vector sum of these momenta:
pi ni = p₁i + p₂i = (1.404 + 2.415) × 10⁷ kg⋅m/s = 3.819 × 10⁷ kg⋅m/s
Find the final velocity and direction of the system. Since the two asteroids stick together, final mass is the sum of their initial masses:
mf = m₁ + m₂ = (18 × 10³ kg) + (23 × 10³ kg) = 41 × 10³ kg
To find the final velocity, using the law of conservation of momentum again:
pf in = mf vfin
Since momentum is conserved:
pfin = pini
Therefore:
mf vfin = pini
vfin = pini / mf = (3.819 × 10⁷ kg⋅m/s) / (41 × 10³ kg) = 930.49 m/s
To find the direction of the final velocity, using trigonometry, define the x-axis to be parallel to the initial velocity of the first asteroid, and the y-axis to be perpendicular to the x-axis. Initial velocity of first asteroid has components:
v₁ix = v₁i cos(15°) = 758.19 m/s
v₁iy = v₁i sin(15°) = 199.78 m/s
Similarly, the initial velocity of the second asteroid has components:
v₂ix = v₂i cos(-15°) = 1041.02 m/s
v₂iy = v₂i sin(-15°) = -269.41 m/s
(Note that we use -15° for the second asteroid since its velocity makes an angle of 165° with respect to the x-axis.)
The total momentum of the system has components:
pfinx = pini = 3.819 × 10⁷ kg⋅m/s
pfiny = 0
Therefore, the final velocity of the system makes an angle θ with respect to the x-axis, where:
tan θ = pfiny / pfinx = 0
Since the y-component of the final velocity is zero, the final velocity is parallel to the x-axis.
Therefore, the direction of the final velocity with respect to the velocity of the first asteroid is the same as the direction of the initial velocity of the first asteroid, which is 15° with respect to the x-axis.
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