A manufacturing firm has hired your company, Acoustical Consulting, to help with a problem. Their employees are complaining about the annoying hum from a piece of machinery. Using a frequency meter, you quickly determine that the machine emits a rather loud sound at 1100 Hz. After investigating, you tell the owner that you cannot solve the problem entirely, but you can at least improve the situation by eliminating reflections of this sound from the walls. You propose to do this by installing mesh screens in front of the walls. A portion of the sound will reflect from the mesh; the rest will pass through the mesh and reflect from the wall.How far should the mesh be placed in front of the wall for this scheme to work?
Answers
Answer: 7.7cm
Explanation:
If i want to set up destructive interference, meaning that the reflection will be half (½) of the wavelength out of phase, or the distance is ¼ of a wavelength.
v.s = Speed of sound = 340 m/s ( some books may use 343 m/s, this change varies due to change in temperature and humidity.)
f = 1100 hz
λ = v.s / f
λ = 340 m/s / 1400 Hz
λ = .3091 m
Recall that the distance is ¼ of the wavelength,
.3091/4 = 0.0773 m
Distance used would be = 7.7 cm
Related Questions
A voltage of 164,112 V in a transmission line is reduced to 65,270 V at the area substation, to 13,115 V at the distributing substation and finally to 894 V at a utility pole outside your house. What turn ratio Ns/Np is required for entire process.
Answers
Turn ratio Ns/Np is equal to the ratio of voltage between the secondary (lower voltage) and the primary (higher voltage).
Ns/Np = Vs/Vp = 894/164112
Ns/Np = 0.00545
12. A baseball (m = 0.14 kg) with initial velocity of -40 m/s (90 mph) is hit. It leaves the bat with a velocity of 60m/s after 0.001s. What is the impulse and average net force applied to the ball by the bat?
Answers
Answer:
the impulse is 14 kg-m/s and the net force applied is 14000 N
Explanation:
Given that,
The mass of a baseball, m = 0.14 kg
Initial velocity of the baseball, u = -40 m/s
Final velocity, v = 60 m/s
Time, t = 0.001 s
We need to find the impulse and average net force applied to the ball by the bat.
Impulse = change in momentum
i.e.
J = m(v-u)
J = 0.14 × (60-(-40))
J = 14 kg-m/s
Now,
J = Ft
F is average force applied to the ball
So,
\(F=\dfrac{J}{t}\\\\F=\dfrac{14}{0.001}\\\\F=14000\ N\)
So, the impulse is 14 kg-m/s and the net force applied is 14000 N.
Find the moment of inertia about the y-axis for three masses in an equilateral triangle if m = 2.00 kg and the sides are 0.500 m. (The connecting rods are massless).
Answers
The centroid of an equilateral triangle is the intersection point of its medians, which is also the center of mass. The medians of an equilateral triangle are equal in length and intersect at a point that is two-thirds of the way from each vertex to the opposite side. Therefore, the distance from the centroid to each vertex is:
h = (√3/2) s
where s is the length of a side. Substituting s = 0.500 m, we get:
h = (√3/2) (0.500 m) ≈ 0.433 m
The moment of inertia of an equilateral triangle with respect to its centroid is:
I = (1/12) m s^2
Substituting m = 2.00 kg and s = 0.500 m, we get:
I = (1/12) (2.00 kg) (0.500 m)^2 = 0.0417 kg m^2
Now, we can use the parallel axis theorem to find the moment of inertia about the y-axis. The parallel axis theorem states that the moment of inertia about any axis parallel to the centroidal axis is equal to the moment of inertia about the centroidal axis plus the product of the total mass and the square of the distance between the two axes.
In this case, the y-axis is parallel to the centroidal axis and passes through the center of the equilateral triangle. The distance between the two axes is the distance from the centroid to the center, which is:
d = h/2 = (√3/4) s
Substituting s = 0.500 m, we get:
d = (√3/4) (0.500 m) ≈ 0.2165 m
The total mass of the system is:
M = 3m = 6.00 kg
Therefore, the moment of inertia about the y-axis is:
Iy = I + Md^2 = 0.0417 kg m^2 + (6.00 kg) (0.2165 m)^2 ≈ 0.573 kg m^2
So, the moment of inertia about the y-axis for three masses in an equilateral triangle with m = 2.00 kg and sides of 0.500 m is approximately 0.573 kg m^2.
what two things make up an ionic bond?
Answers
PLEASE HELP! Will give BRAINILIEST! An amplifier can magnify the intensity of sound waves by a factor of 1,000. If a 30dB sound is fed into the amplifier, how many decibels will come out?
Answers
Answer:
30,000dB
Explanation:
30,000dB because 30 multiplied by a factor of 1000 is 30,000
Hope this helps! :)
Identify the characteristic of the transverse wave that halved from wave A (black) to wave B (green).
a) amplitude
b) crest
c) trough
d) wavelength
Answers
Answer:
D
Explanation:
The wavelength of wave B (green) is half of the wavelength of wave A (black). Therefore, option (d) is correct.
What is wavelength?The wavelength of a wave can be defined as the distance between the two adjacent points which are in phase with respect to each other. The separation between the two adjacent crests or adjacent troughs on a wave is also known as wavelength.
The relationship between the wavelength (λ) of the wave, frequency (ν), and speed of the wave (V) is:
V = νλ
Transverse waves oscillate along routes that are perpendicular to the direction in which the wave is propagating forward. In a transverse wave, particles of matter are oscillated up and down about their mean position instead of following the path of the wave.
Therefore, the wavelength of the transverse wave halved from black wave A to green wave B.
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13. What is the acceleration of a 1,000-kilogram truck with a net force of 7,000 newtons?
Answers
Answer:
7 m/s²Explanation:
The acceleration of an object given it's mass and the force acting on it can be found by using the formula
\(a = \frac{f}{m} \\ \)
f is the force
m is the mass
From the question we have
\(a = \frac{7000}{1000} = 7 \\ \)
We have the final answer as
7 m/s²Hope this helps you
Barney walks at a velocity of 1.7 meters/second on an inclined plane which has an angle of 18.5 with the ground what is the horizontal component of Barney’s velocity
Answers
Answer:
Explanation:
The horizontal velocity is 1.61.
You know you can provide 600 W
of power to move large objects. You need to move a 60-kg
safe up to a storage loft, 18 m
above the floor.
Part A
With what average speed can you pull the safe straight up?
Answers
A. The average speed you can use to pull the safe is 1.02 m/s
B. The time needed to pull the safe up is 17.65 s
A. How do i determine the velocity?First, we shall obtain the force. This is shown below:
Mass of safe (m) = 60 KgAcceleration due to gravity (g) = 9.8 m/s² Force (F) =?F = mg
F = 60 × 9.8
F = 588 N
Finally, we shall obtain the average speed. Details below:
Power = 600 WForce = 588 NAverage speed =?Power = force × average speed
600 = 588 × average speed
Divide both sides by 588
Average speed = 600 / 588
Average speed = 1.02 m/s
B. How do i determine the time?The time needed to pull the safe up can be obtained as follow:
Average speed = 1.02 m/sTotal distance = 18 mTime = ?Time = Total distance / average speed
Time = 18 / 1.02
Time = 17.65 s
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Complete question:
You know you can provide 600 W
of power to move large objects. You need to move a 60-kg
safe up to a storage loft, 18 m
above the floor.
Part A
With what average speed can you pull the safe straight up?
Part B
What is the time needed to pull the safe up?
How precise is the measurement of length? Of volume?
Answers
Answer:
The precision corresponds to the least count of the measurements, which is 0.1 cm 0.1 c m for the length of the box. In a similar manner, the precision of the volume is 0.01×103 cm3=10 cm3 0.01 × 10 3 c m 3 = 10 c m 3 .
What do you picture in your mind when you read this simile?
Bolt runs as fast as lighting.
Bolt runs very fast.
Bolt runs in a straight line.
Bolt runs in a wavy manner.
Bolt's each step produces thunder.
Answers
When reading the simile "Bolt runs as fast as lightning," the most appropriate visual interpretation would be that "Bolt runs very fast."
This simile compares Bolt's speed to that of lightning, which is known for its incredible swiftness. The intention is to emphasize Bolt's exceptional speed by equating it to the rapid movement of lightning.
While the simile highlights Bolt's remarkable speed, it does not specify the manner in which he runs or the impact of each step. Therefore, the options suggesting Bolt runs in a straight line, in a wavy manner, or that each step produces thunder are not directly implied by the simile itself. These additional details go beyond the comparison of speed and introduce elements that are not explicitly mentioned.
Hence, the most accurate interpretation based solely on the simile is that Bolt runs very fast, comparable to the speed of lightning.
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If a dog that has moved has a displacement of zero, it means that the dog's initial position and final position are the same. Is it T or F
Answers
Answer:
true
Explanation:
the dog hasn't moved, displacement has direction, and there is no movement or direction involved, his final position and initial are the same
A car going initially with a velocity 13.5 m/s accelerates at a rate of 1.9 m/s 2 for 6.2 s. It then accelerates at a rate of -1.2 m/s2 until it stops. a) Find the car’s maximum speed b) Find the total time from the start of the first acceleration until the car is stopped c) What’s the total distance the car travels?
Answers
(a) For the first 6.2 s, the car has velocity at time t given by
\(v(t)=13.5\dfrac{\rm m}{\rm s}+\left(1.9\dfrac{\rm m}{\mathrm s^2}\right)t\)
so that after 6.2 s, it attains a velocity of
\(v(6.2\,\mathrm s)=25.28\dfrac{\rm m}{\rm s}\)
For any time t after 6.2 s, its velocity is given by
\(v(t)=25.28\dfrac{\rm m}{\rm s}+\left(-1.2\dfrac{\rm m}{\mathrm s^2}\right)t\)
which tells us the velocity only falls from this point onward. This means the maximum speed is 25.28 m/s, or about 25.3 m/s.
(b) Solve for t (after 6.2 s) that makes v(t) = 0 :
\(25.28\dfrac{\rm m}{\rm s}+\left(-1.2\dfrac{\rm m}{\mathrm s^2}\right)t=0\)
\(\implies t\approx21.067\,\mathrm s\)
It takes the car about 21.2 s to come to a rest, so the car travels a total of about 6.2 s + 21.2 s = 27.4 s.
(c) For the first 6.2 s, the car undergoes a displacement at time t of
\(x(t)=\left(13.5\dfrac{\rm m}{\rm s}\right)(6.2\,\mathrm s)+\dfrac12\left(1.9\dfrac{\rm m}{\mathrm s^2}\right)(6.2\,\mathrm s)^2\)
\(\implies x\approx120.218\,\mathrm m\)
For time t beyond 6.2 s, its displacement is
\(x(t)=120.218\,\mathrm m+\left(25.28\dfrac{\rm m}{\rm s}\right)t+\dfrac12\left(-1.2\dfrac{\rm m}{\mathrm s^2}\right)t^2\)
The car comes to a rest after 21.2 s (accelerating at a rate of -1.2 m/s^2), so that its total displacement is
\(x(21.2\,\mathrm s)\approx386.49\,\mathrm m\)
so the car travels a total distance of about 387 m.
1. Which of the following does not affect the resistance of a wire?
a) Length
b) Temperature
c) Usage time
d) Cross-sectional area
2. If a 12V battery is passing current through a resistor with a current of 2A, what is the value of the resistor?
a 24resistance
b) 14resistance
c) 10resistance
d) 6resistance
3. Describe the differences between series and parallel circuits.
4. A circuit contains resistors of 8resistance and 4resistance，what is combined resistance if the resistors are combined:
a) In series
b) In parallel
5. A 0.5A current is passing across three resistors of 8resistance, 4resistance and 12resistance that are linked in series.
What is the potential difference of the circuit?
6. Wire A has a resistance of 24resistance. If wire B is double the length and has a diameter four times as large as wire A, what is the resistance of wire B?
Answers
An insect lands 0.1m from the centre of a turn table while the record is turning at 55 rev/min at what linear speed will the insect be carried
collision with the near stationary photograph
Answers
The linear speed will be the insect be 0.5759 meter/second carried collision with the near stationary photograph.
What is speed?
Speed is distance travelled by the object per unit time. Due to having no direction and only having magnitude, speed is a scalar quantity With SI unit meter/second.
Given that an insect lands 0.1m from the center of the turn table.
Rotational speed of the turn table = 55 rev/min
= (55×2π/60) rad/second
= 5.759 rad/second.
Hence, the speed of the insect be = Rotational speed × length
= 5.759 rad/second × 0.1 M.
= 0.5759 meter/second.
Therefore, the speed of the insect be 0.5759 meter/second.
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Why is the size of a telescope's lens or mirror important for gathering information about distant objects?A. Because magnification is better with smaller lenses.B. Because big telescopes are hard to manage.C. Because the goal is to gather as much electromagnetic radiation as possible.
Answers
Given:
The size of the telescope's lens or mirror is important for gathering information about distant objects.
To find:
The reason
Explanation:
The telescope's lenses or the mirrors gather light and we are able to see the things that are really far away. The more big the size of the lens or the mirror, the more light they can gather.
Hence, gathering as much electromagnetic radiation as possible is the correct option.
The minute hand of a clock on a clock tower is 1 meter long. What is the tangential speed at the tip of that hand
Answers
Answer:
ω = θ / t
1 rev = 2 pi rad
t = 60 sec / min * 60 min / hr = 3600 sec / hr
v = ω R tangential speed
v = (2 pi m / hr) / (3600 sec / hr) = .00175 m/sec
As a check
s = 2 pi * 1 m = 6.28 meters around dial
It takes 3600 sec for 1 rotation of the minute hand
v = 6.28 / 3600 = .0017 m/s
Macmillan Learning
A black mamba snake has a length of 2.60 m and a top speed of 4.50 m/s. Suppose a mongoose and a black mamba find
themselves nose to nose. In an effort to escape, the snake accelerates past the mongoose at 8.37 m/s² from rest.
How much time ftop does it take the snake to reach its top
speed?
How far dsnake does the snake travel in that time?
How much time freact does the mongoose have to react before
the black mamba's tail passes the mongoose's nose?
ftop
dsnake =
freact=
S
m
S
Answers
The black mamba travels a distance of 2.0828 m, which is less than its length of 4.50 m.
How far dsnake does the snake travel in that time?The first equation of motion states:
vf = at + vi
A top speed is _f.
Initial or lowest speed is v i, and acceleration is a.
2.60 = 4.50 t
t +0 = 1.28571sec
The snake needs 1.28571 seconds to attain its peak speed.
Part B:
The second equation of motion states:
S=0.5(4.50) S=vit+at2 w i=0 (1.28571)
2 S = 2.0828m
In that period, the snake moves 2.0828 metres.
Part C:
The black mamba travels a distance of 2.0828 m, which is less than its length of 3.12 m.
2.0828 m<3.12 m
A potential exists for monkeys to capture a black mamba.
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A baseball player hits a 0.15 kg 0.15kg0, point, 15, start text, k, g, end text baseball that is initially at rest, changing its momentum by 11 kg ⋅ m s 11 s kg⋅m 11, start fraction, start text, k, g, end text, dot, start text, m, end text, divided by, start text, s, end text, end fraction.
Answers
Answer:
73.3m/s
Explanation:
We can find the velocity of the player.
Momentum = mass * velocity
Given
Mass = 0.15kg
Momentum = 11kgm/s
Get the velocity
Velocity = Momentum/Mass
Velocity = 11/0.15
Velocity = 73.3m/s
Hence the velocity of the player is 73.3m/s
Which statement is a scientifically accurate description of velocity?
A, Walking south along the two-mile canyon trail generally takes less time than traveling the same trail north because walking south is all downhill.
B, The hiker began hiking the park's five-mile north hiking trail at 8:00 a.m. with plenty of daylight left to complete the hike before dark.
C, The motorcyclist traveled along a highway at 55 mph and reached the campsite in less than the two-hour estimated time.
D, The boat traveled from the dock north to the 200-meter marker in the bay in less than 5 minutes, giving the passengers several more hours to fish.
Answers
Answer: D
Explanation:
north=direction
200-meter= distance
less than 5 minutes= time
discuss four contributing factors that may lead to an increase of learners abusing substance in scools
Answers
Answer:
What are the four contributing factors that may lead to an increase of learners abusing substances in school?
Peer pressure. ...
Socializing.
Community.
Socioeconomic status.
Stress.What are the four contributing factors that may lead to an increase of learners abusing substances in school?
Peer pressure. ...
Socializing.
Community.
Socioeconomic status.
Stress.What are the four contributing factors that may lead to an increase of learners abusing substances in school?
Peer pressure. ...
Explanation:
A piece of metal at the bottom of a beaker is 0.50m below the eye. If water is poured into the cylinder to a depth of 0.24m . how much closer does the metal appear? (Refractive index of water = 4/3)
Answers
If a piece of metal at the bottom of a beaker is 0.50m below the eye, and water is poured into the cylinder to a depth of 0.24m, Then the metal appears closer by 0.38m.
To calculate how much closer the metal appears, we can use the lens maker's formula, which relates the object distance, image distance, and focal length of a lens or in this case, the refractive index of water.
The formula is:
1/f = (n - 1) x (1/R1 - 1/R2)
where f is the focal length, n is the refractive index of the medium (water in this case), R1 is the radius of curvature of the first surface of the medium (in this case, the bottom surface of the beaker), and R2 is the radius of curvature of the second surface of the medium (in this case, the air-water interface at the top of the water level).
Assuming the radius of curvature of both surfaces is large and the surfaces are nearly flat, we can approximate R1 and R2 as infinity, so the formula simplifies to:
1/f = (n - 1) x (1/R2)
Since the piece of metal is at the bottom of the beaker, it acts as the object, and the eye acts as the observer. Initially, the object distance is the distance from the bottom of the beaker to the eye, which is 0.50m.
When water is poured into the beaker to a depth of 0.24m, the new object distance is the distance from the bottom of the beaker to the water level, which is 0.50m - 0.24m = 0.26m.
To calculate the image distance, we can use the thin lens equation:
1/f = 1/o + 1/i
where o is the object distance, and i is the image distance.
Solving for i, we get:
i = (1/f - 1/o)^-1
Since we know that the object distance o is 0.26m, we just need to calculate the focal length f using the lens maker's formula.
1/f = (n - 1) x (1/R2) = (4/3 - 1) x (1/0.24m) = 1/0.72m
f = 0.72m
Plugging in the values, we get:
i = (1/0.72m - 1/0.26m)^-1 = 0.12m
Therefore, the metal appears closer by 0.50m - 0.12m = 0.38m.
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A –8.0-µC charge is located 0.45 m to the left of a +6.0-µC charge. What is the magnitude and direction of the electrostatic force on the positive charge?
Answers
Answer:
2.133 N to the left
Explanation:
We can represent the situation with the following equation:
Then, the magnitude can be calculated as:
\(\begin{gathered} F=k\frac{q_1q_2}{r^2} \\ \\ \text{ Where k = 9 x 10}^9\text{ N m}^2\text{ /C}^2 \end{gathered}\)Where q1 and q2 are the charges and r is the distance. So, replacing q1 = 8 x 10^(-6) C, q2 = 6.0 x 10^(-6) C, and r = 0.45 m, we get:
\(F=(9\times10^9)\frac{(8\times10^{-6})(6\times10^{-6})}{0.45^2}=2.133\text{ N}\)Therefore, the magnitude of the electrostatic force is 2.133 N and the direction is to the left.
which of the following are not units used to measure energy?
a. joules
b. newtons
c. BTU
d. calories
Answers
Answer:
The BTU, or British thermal unit, is actually a measure of heat.
A pendulum with a length of 2 m has a period of 2.8 s. What is the period of a pendulum with a length of 8 m
Answers
Answer:
P = 2 pi (L / g)^1/2
P2 / P1 = (8 / 2)^1/2 = 2
The period would be twice as long or 5.6 sec.
A sound level meter 6.0 m from a jet engine measures 110.0 dB. the sound power output of the jet engine , assuming uniform spherical spreading of the sound and neglecting absorption in the air is___W
Answers
dyed I don't it sorryvplss
Suppose that scientists observe violent gas eruptions on a planet with an acceleration due to gravity of 3.8 m/s2. The jets throw sand and dust about 75 m above the surface.
What is the speed i of the material just as it leaves the surface?
Scientists estimate that the jets originate as high‑pressure gas speeds through vents just below ground at about 160 km/h. How much energy per kilogram of material does the jet lose to non conservative forces as the high‑speed matter forces its way to the surface and into the air?
Answers
Answer:
linarkuoouonpnpjjñihy
Explanation:
Let to the right be the positive direction.
A 25.8 g marble sliding to the right at 21.0
cm/s overtakes and collides with a 12.4 g
marble moving in the same direction at 13.8
cm/s. After the collision, the 12.4 g marble
moves to the right at 23.9 cm/s.
Find the velocity of the 25.8 g marble after
the collision.
Answer in units of cm/s. Answer in units
of cm/s.
Answers
The final velocity of the 25.8 g marble after the collision is 16.15 cm/s.
What is the velocity of the 25.8 g marble after the collision?
The velocity of the 25.8 g marble after the collision is calculated as follows;
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
where;
m₁ is the mass of 25.8 g marblem₂ is the mass of 12.4 g marbleu is their initial speedsv is their final speedsThe final velocity of the 25.8 g marble after the collision is calculated as;
( 25.8 x 21 ) + ( 12.4 x 13.8 ) = ( 12.4 x 23.9 ) + ( 25.8v )
712.92 = 296.36 + 25.8v
25.8v = 416.56
v = 416.56 / 25.8
v = 16.15 cm/s
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The
- is where the worker applies a tool to materials.
Select the best option.
Which one is it
Answers
Answer:
Point of operation.
Explanation:
A tool can be defined as a mechanical or electronic apparatus that is typically used for performance of specific tasks.
This ultimately implies that, a tool is generally used by workers to perform their day-to-day tasks, duties or job functions.
All work related activities in the workshop have a point of operation i.e the particular point where a task is to be performed such as cutting a wood.
Hence, the point of operation is where the worker applies a tool to materials.
If the mass of a basketball is 18 times that of a tennis mass, can they ever have the same momentum? Explain your answer
Answers
Answer:
Yes
Explanation:
Yes. The momentum is the same when the speed of the tennis ball is 18 times greater than the speed of the basketball and the velocities of both objects are in the same direction.