Answer:
r₂ = 0.316 m
Explanation:
The sound level is expressed in decibels, therefore let's find the intensity for the new location
β = 10 log [tex]\frac{I}{I_o}[/tex]
let's write this expression for our case
β₁ = 10 log \frac{I_1}{I_o}
β₂ = 10 log \frac{I_2}{I_o}
β₂ -β₁ = 10 ( [tex]log \frac{I_2}{I_o} - log \frac{I_1}{I_o}[/tex])
β₂ - β₁ = 10 [tex]log \frac{I_2}{I_1}[/tex]
log \frac{I_2}{I_1} = [tex]\frac{60 - 20}{10}[/tex] = 3
[tex]\frac{I_2}{I_1}[/tex] = 10³
I₂ = 10³ I₁
having the relationship between the intensities, we can use the definition of intensity which is the power per unit area
I = P / A
P = I A
the area is of a sphere
A = 4π r²
the power of the sound does not change, so we can write it for the two points
P = I₁ A₁ = I₂ A₂
I₁ r₁² = I₂ r₂²
we substitute the ratio of intensities
I₁ r₁² = (10³ I₁ ) r₂²
r₁² = 10³ r₂²
r₂ = r₁ / √10³
we calculate
r₂ = [tex]\frac{10.0}{\sqrt{10^3} }[/tex]
r₂ = 0.316 m
a 7 kg object moving 10 m/s Right collides with a 14 kg object at rest. If after the collision the 7kg object is at rest and the 14 kg object is moving, what is the velocity of the 14 kg object after the collision?
Answer:
v2(final)=5 m/s
Explanation:
we are going to use the conservation of momentum here
m1*v1(initial)+m2*v2(initial)=m1*v1(final)+m2v2(final)
m1=7 kg v1(initial)=10 m/s
m2=14 kg v2(initial)=0 m/s (bc initially it is at rest)
v1(final)= 0 m/s (m1 stops moving after the collision)
v2(final)=?
7*10+14*0=7*0+14*v2(final)
70=14v2(final)
v2(final)=70/14 m/s=5 m/s
a glass rod is given a positive charge by rubbing it with silk. how did the rod become positive ?
Answer:
When the glass rod is rubbed with silk, the silk strips electrons from the rod, leaving it a positive charge. When the hard rubber rod is rubbed with wool, it gains electrons from the wool, gaining a negative charge.
Explanation:
What causes an electric field?
Answer: The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. ... The force created by the electric field is much stronger than the force created by the magnetic field.
Explanation: An electric field is an invisible force field created by the attraction and repulsion of electrical charges (the cause of electric flow), and is measured in Volts per meter (V/m).
Answer:
The electric field is produced by stationary charges, and the magnetic field by moving charges (currents); these two are often described as the sources of the field. The force created by the electric field is much stronger than the force created by the magnetic field.
Explanation:
Ggl
Students are asked to design an experiment to confirm that the pressure and volume of an ideal gas are inversely proportional. They use a cylinder containing an ideal gas that has a plunger equipped with a pressure sensor. They perform several trials, and in each trial they start with the gas at the same initial pressure and volume. The students then quickly push the plunger so that the gas achieves a different final pressure and volume. After analyzing their results, they determine that the final pressures and volumes do not follow an inversely proportional relationship. Which of the following refinements to the procedure would show the inverse proportionality between pressure and volume?
A. Compress the gas slowly so that the temperature remains constant.
B. Perform more trials to obtain more data points.
C. Discard data points that do not show inverse proportionality between pressure and volume.
D. Compress the plunger even faster so that the compression is effectively instantaneous.
Answer:
the answers the correct one is A
Explanation:
Let's analyze the situation, the expression for ideal gases is
PV = n R T
in this case n is the number of moles of the gas remains constant, so we see that there is a relationship between volume, pressure and temperature.
For the experiment we are conducting we must ensure that the temperature remains constant, one way to achieve this is by placing a small thermometer on the surface of the cylinder.
By rapidly compressing part of the work done, it is converted into internal energy of the gas molecules, and from there it is transformed into its temperature. One way to reduce this effect is to COMPRESS SLOWLY and thus keep the temperature constant.
This method of allowing to check
P V = cte
when checking the answers the correct one is A
the atom of an element x has 21protrons and 23neutrons. What is the
(a) Electron number
(b) Mass number
(c) Neutron number
At noon, ship A is 110 km west of ship B. Ship A is sailing east at 20 km/h and ship B is sailing north at 15 km/h. How fast is the distance between the ships changing at 4:00 PM
Answer:
[tex]4.47\ \text{km/h}[/tex]
Explanation:
[tex]\dfrac{da}{dt}[/tex] = Rate at which the distance between A and starting point of B is changing = -20 km/h
[tex]\dfrac{db}{dt}[/tex] = Rate at which the distance of B is changing = 15 km/h
[tex]\dfrac{dc}{dt}[/tex] = Rate at which the distance between A and B is changing
Time after which the rate at which the distance between A and B is changing is 4 hours
Distance covered by A in 4 hours = [tex]20\times 4=80\ \text{km}[/tex]
a = Distance remaining to the start point of B = [tex]110-80=30\ \text{km}[/tex]
b = Distance covered by B in 4 hours = [tex]15\times 4=60\ \text{km}[/tex]
Distance between A and B after 4 hours
[tex]c=\sqrt{a^2+b^2}\\\Rightarrow c=\sqrt{30^2+60^2}\\\Rightarrow c=67.08\ \text{km}[/tex]
[tex]c^2=a^2+b^2[/tex]
Differentiating with respect to time we get
[tex]c\dfrac{dc}{dt}=a\dfrac{da}{dt}+b\dfrac{db}{dt}\\\Rightarrow \dfrac{dc}{dt}=\dfrac{a\dfrac{da}{dt}+b\dfrac{db}{dt}}{c}\\\Rightarrow \dfrac{dc}{dt}=\dfrac{30\times -20+60\times 15}{67.08}\\\Rightarrow \dfrac{dc}{dt}=4.47\ \text{km/h}[/tex]
The rate at which the distance between the ships is changing at 4 PM is [tex]4.47\ \text{km/h}[/tex].
A car driver spends 3hrs driving at an average speed of 80km/hr, stops for 30 minutes to
have some rest, and then drives at an average speed of 90km/hr for 2 hours.
Calculate the average speed during the whole journey
Answer:
The average speed throughout the journey was 76.36 kilometers per hour.
Explanation:
Given that a car driver spends 3hrs driving at an average speed of 80km / hr, stops for 30 minutes to have some rest, and then drives at an average speed of 90km / hr for 2 hours, to determine the average speed during the whole journey the following calculation must be performed:
80 km / h x 3 = 240 km
90 km / h x 2 = 180 km
240 + 180 = 420 km
3 + 2 + 0.5 = 5.5 hours
420 / 5.5 = 76.36
Thus, the average speed throughout the journey was 76.36 kilometers per hour.
Your eyes form upside-down images, which are then flipped right-side-up by our brains.
True
False
Answer:
I believe it is true, but our brains don’t do it, I think it is the lenses in our eyes that do it. I might be wrong tho
Explanation:
Answer:
Yes it is true that our eyes form upside-down images, which are flipped right-side-up by our brain.
Scientists have concluded that the uppermost part of the mantle is partially-molten. Which observation helped them reach this conclusion?
Answer:
P and S waves slow down when they reach this layer. The asthenosphere, also known as the magma chamber, is the uppermost component of the mantle. This layer is partially molten and is a ductile zone in a tectonically poor state.
It's almost hard and seismic waves move through the asthenosphere at a slow rate. The fragile lithosphere and the uppermost portion of the asthenosphere are assumed to be rigid.
seismic waves travel more quickly through denser materials and therefore generally travel more quickly with the depth it moves more slowly through a liquid than a solid. Molten areas within the Earth slow down P waves and stop S waves because their shearing motion cannot be transmitted through a liquid. Partially molten areas may slow down the P waves and attenuate or weaken S waves.
hope this helps...
S and P wave slow down and stop in the uppermost part of the mantle. - For this, scientists have concluded that the uppermost part of the mantle is partially-molten.
What is mantle?A planetary body's mantle is a layer that is surrounded by the crust on top and the core underneath. The largest and most substantial layer of a planetary body, mantles are often comprised of rock or ice. Planetary bodies that have undergone density differentiation typically have mantles. Mantles are found on all terrestrial planets (including Earth), many asteroids, and a few planetary moons.
Between the crust and the outer core, there is a silicate rock layer known as the Earth's mantle. Despite being mostly solid, it behaves like a viscous fluid over geological time. Oceanic crust is created by the partial melting of the mantle at mid-ocean ridges, and continental crust is created by the partial melting of the mantle at subduction zones.
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Water can form large dewdrops in nature how would droplets made of isopropyl alcohol instead of water be different
Answer:
isopropyl alcohol would form smaller droplets, because it has lower surface tension than water has
Explanation:
Ap3x
The droplets made of isopropyl alcohol instead of water be smaller due to surface tension.
What is droplets?The single drop of a liquid in the form of sphere is called droplet.
Water can form large dewdrops in nature. Isopropyl alcohol would form smaller droplets, because it has lower surface tension than water.
Surface tension is the property of the liquid to acquire minimum surface area.
Thus, droplets made of isopropyl alcohol instead of water be smaller.
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A woman shouts at a boy who is underwater what happens to the speed of the sound wave as it moves from the air into the water
Answer:
B. it increases
Explanation:
As shown in the table provided, the speed of sound in water (1493 m/s) is greater than the speed of sound in air (346 m/s).
Answer:
B is the correct answer.
Explanation:
Two students are sitting 1.50 m apart. One student has a mass of 70.0 kg and
the other has a mass of 52.0 kg. What is the gravitational force between them?
A. 8.01 x 10-9
B. 1.08 x 10-2
C. 2.28 x 10-8
Answer:
B
Explanation:
PLEASE HELP
the graph shows a plot of an objects velocity versus time for 15 seconds. is the acceleration of the object constant or changing? how do you know? what does this tell you about the net force on the object?
Answer:
It cannot be constant because if it does not change and each time it increases its strength and speed.
Explanation:
2.- a person weighing 70 kg travels at 2m / s. What is the value of his kinetic energy?
Answer:18 watts
Explanation:i just got this question trust me
\
What is Newton's scientific view?
Answer:
Newton's first law of motion concerns any object that has no force applied to it.
Explanation:
three laws of motion and the law of universal gravitation.
20. How does a paraxylene crystallizer operate?
In the CrystPX Technology process, suspension crystallization of paraxylene (PX) in the xylene isomer mixture is used to produce paraxylene crystals. At the back end of the process, high paraxylene recovery is obtained by operating the crystallizers at colder temperatures.
Paraxylene crystals are created using the CrystPX Technology by suspending paraxylene (PX) in a mixture of xylene isomers. High paraxylene recovery is achieved at the end of the process by running the crystallizers at lower temperatures.
What does a paraxylene crystallizer operate?The paraxylene technology from BP, a novel method using single stage crystallization for paraxylene (pX) recovery, is licensed exclusively to Lummus Technology for use around the world.
This cutting-edge architecture makes the Lummus Technology/BP pX crystallization technology the most energy-efficient paraxylene recovery process, together with excellent feed impurity tolerance and low total unit fuel consumption.
The Lummus Technology/BP paraxylene process has a high degree of dependability, is inexpensive, and can take a variety of feed compositions.
Therefore, With the aid of isomerization over a non-noble metal catalyst, the yield of xylene is improved even further. Optimized fractionation lowers reboiler duty, resulting in less energy use and emissions.
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Chris used a non plane mirror to check out an box resting on a shelf. He wanted to find
the focal length of the mirror. The image of the box was located 15 cm behind the mirror
and the box was placed 19 cm from the mirror.
Chris used a non-plane mirror to check out a box resting on a shelf, the focal length of the mirror is mathematically given as
f=8.38cm
What is the focal length of the mirror?Question Parameter(s):
The image of the box was located 15 cm behind the mirror
and the box was placed 19 cm from the mirror.
Generally, the equation for the focal length is mathematically given as
1/f=1/u+1/v
Therefore
1/f=1/15+1/19
f=8.3823529cm
In conclusion, the focal length of the mirror
f=8.3823529cm
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A mass of 3 kg stretches a spring 9m. The mass is acted on by an external force of 2 AND. The Mass moves in a medium that imparts a viscous force of 1 N when the speed of the mass is 4m/sec The mass is pulled down 8 cm below its equilibrium position, and then set in motion inthe upward direction with a velocity of 5 m/sec. State the initial value problem describing the motion of the mass. DO NOT SOLVE.
Answer:
k y -b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]
give us some initial conditions
1) friction force fr = 1N when v = 4m / s
2) an initial displacement of x = 0.08 m for t=0 s
Explanation:
In this exercise, you are asked to state the problem you are posing. We are going to find the equation of motion for this exercise. Let's start with Newton's second law
Let's set a reference system with the y-axis in a vertical and positive direction upwards.
We have four forces: an external downward force, negative in sign, the but that goes down and is negative, the Hook force that goes up and is positive and the friction force that opposes the movement, in this case it goes down being negative
let's write Newton's second law
F_e -F -fr - W = m a
where
F_e = -kDy = - k y
fr = - b v = -b dy / dt
W = mg
we substitute for the specific case, that is, using the signs
k y -b [tex]\frac{dy}{dt}[/tex] - m g - F = m [tex]\frac{d^2y}{dt^2}[/tex]
In the initial condition of the problem, before starting the movement, the friction force is zero and the acceleration is also zero
k y - m g - F = 0
from this equation you can find the spring constant, y= 9m and F=2 N
It is not clear if when the movement starts this external force becomes zero, but since it balances the weight we can eliminate the two forces that have the same magnitude and opposite direction, so the equation remains
k y - b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]
give us some initial conditions
1) friction force fr = 1N when v = 4m / s
2) an initial displacement of x = 0.08 m for t=0 s
therefore, to initiate the movement, a small external force F 'is applied that moves the system to a new equilibrium position and this small force F' is made zero, thus initiating an oscillatory movement, described by the equation.
k y -b [tex]\frac{dy}{dt}[/tex]dy / dt = m [tex]\frac{d^2y}{dt^2}[/tex]
This is a differential equation of the second degree, therefore it needs two initial conditions for its complete solution
The initial amount of displacement corresponds to the amplitude of movement A = 0.08 m
A car is moving around a circular track of radius 25m with a speed of 30 m/s. What is the centripetal acceleration of the car? *
A 72 m/s2
B 36 m/s2
C 30 m/s2
D 6 m/s2
Answer:
I don't know how to do it the subject
The centripetal acceleration of the car when there is the radius and the speed is given so it should be considered as the option b. 36 [tex]m/s^2[/tex].
Calculation of the centripetal acceleration of the car:Since
The radius is 25 cm and the speed should be 30 m/s
Now the following formula should be used
Acceleration = speed^2/ radius
= 30^2 / 25
= 900 / 25
= 36 [tex]m/s^2[/tex]
Therefore, The centripetal acceleration of the car should be considered as the option b. 36 [tex]m/s^2[/tex].
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Which of the following best defines
weather?
A. the expanding or contracting of the atmosphere
B. the measurement of the amount of water vapor in the
atmosphere
C. the condition of the atmosphere at a certain time and
place
Help Resources
D. the average air temperature of a specific region
Answer:
I'd say D
Explanation:
because not all weather happens within the atmosphere, and most weather depends on region (lile if your near the equator or not)
If an athlete runs the triathlon of 10 km in 2 hours, what is her average speed in kilometers per hour?
Answer: 5 km per hour
Explanation:
if in 10 km there is 2 hours, then 10 divided by 2 is 5.
Are all harmful effects of smoking reversible? Explain your answer.
Which of the following happens to
density as air pressure decreases?
С C
A. Density increases.
B. Density stays the same.
C. Density decreases.
D. There is no correlation between air pressure and
density.
Explanation:
As pressure increases, with temperature constant, density increases. Conversely when temperature increases, with pressure constant, density decreases. Air density will decrease by about 1% for a decrease of 10 hPa in pressure or 3 °C increase in temperature.
Basic Science!! Helppp
A water balloon weighing 4.5 N rests on a table. The balloon has an area of 2.6 x 10-3
m² in contact with the table. What pressure does the balloon exert on the table?
Answer:
the pressure the balloon exerts on the table is 1,730.77 N/m²
Explanation:
Given;
weight of the water balloon, F = 4.5 N
area of the balloon, A = 2.6 x 10⁻³ m²
The pressure the balloon exerts on the table is calculated as follows;
[tex]P = \frac{F}{A}[/tex]
substitute the given values and solve for pressure, P;
[tex]P = \frac{4.5}{2.6 \times 10^{-3}} \\\\P = 1,730.77 \ N/m^2[/tex]
Therefore, the pressure the balloon exerts on the table is 1,730.77 N/m²
A bird is flying directly toward a stationary bird-watcher and emits a frequency of 1490 Hz. The bird-watcher, however, hears a frequency of 1505 Hz. What is the speed of the bird, expressed as a percentage of the speed of sound
Answer:
The speed of the bird is 1.00% of the speed of sound.
Explanation:
The speed of the bird can be found by using the Doppler equation:
[tex] f = f_{0}(\frac{v - v_{r}}{v - v_{s}}) [/tex]
Where:
v: is the speed of sound = 343 m/s
f₀: is the frequency emitted = 1490 Hz
f: is the frequency observed = 1505 Hz
[tex]v_{r}[/tex]: is the speed of the receiver = 0 (it is stationary)
[tex]v_{s}[/tex]: is the speed of the source =?
The minus sign of [tex]v_{s}[/tex] is because the source is moving towards the receiver.
By solving the above equation for [tex]v_{s}[/tex] we have:
[tex] v_{s} = v - \frac{f_{0}*v}{f} = 343 - \frac{1490*343}{1505} = 3.42 m/s [/tex]
The above speed in terms of the speed of sound is:
[tex]\% v_{s} = \frac{3.42}{343}\times 100 = 1.00 \%[/tex]
Therefore, the speed of the bird is 1.00% of the speed of sound.
I hope it helps you!
Anatomy and Phys PLEASE HELP
you’ve learned about the structures that make up the reproductive system. Imagine that you are so interested in reproductive health that you are exploring careers related to this health field.
For this activity you are going to research careers related to the promotion or treatment of reproductive health and choose one career to focus on. You are going to identify the key factors of the educational path that you would need to take to work in this career, the annual salary that you would earn, the schedule that you may find yourself working, physical requirements for the job, and how long it will take you to achieve this goal.
You will produce a list of 10 or more strengths and weaknesses that will identify why you are qualified for this role.
You will then prepare a list of at least five questions that you would like to ask someone already working in the career. Your questions ought to be relevant to the career you have chosen and should be related to the research that you have conducted.
Answer:
Get to work.
Explanation:
This is not Brainly material. This is a project that you need to get started on and do your best on. It always looks worst before you get started on it. Just sink your teeth in and you'll be finishing it up before you know it.
Answer:
careers related to the promotion or treatment of reproductive health and choose one career to focus on. You are going to identify the key factors of the educational path that you would need to take to work in this career, the annual salary that you would earn, the schedule that you may find yourself working, physical requirements for the job, and how long it will take you to achieve this goal.
Explanation:
A wheel rotates about a fixed axis with an initial angular velocity of 24 rad/s. During a 4 s interval the angular velocity decreases to 14 rad/s. Assume that the angular acceleration is constant during the 4 s interval. How many radians does the wheel turn through during the 4 s interval
Answer:
[tex]\theta=76\ rad[/tex]
Explanation:
Hoven that,
Initial angular velocity of the wheel = 24 rad/s
Final angular velocity = 14 m/s
Time, t = 4 s
We need to find how many radians does the wheel turn through during the 4 s interval. Let the displacement is [tex]\theta[/tex]. Using second equation of rotational kinematics to find it such that,
[tex]\theta=\omega_i t+\dfrac{1}{2}\alpha t^2[/tex]
Where
[tex]\alpha[/tex] is angular acceleration
[tex]\alpha =\dfrac{\omega_f-\omega_i}{t}\\\\\alpha =\dfrac{14-24}{4}\\\\\alpha =-2.5\ rad/s^2[/tex]
So,
[tex]\theta=24\times 4+\dfrac{1}{2}\times (-2.5)\times 4^2\\\\\theta=76\ rad[/tex]
So, it will turn 76 radian during the 4 s interval.
A person applies a constant force of 100 N on an object of mass 20 kg. The object moves horizontally at a constant speed of 0.20 m/s through a distance of 0.80 m. What is the net work done on the object
Answer:
the net work done on the object is 80 J.
Explanation:
Given;
force applied on the object, F = 100 N
mass of the object, m = 20 kg
speed of the object, v = 0.2 m/s
distance moved by the object, d = 0.8 m
The net work done on the object is calculated as follows;
W = F x d
W = 100 N x 0.8 m
W = 80 J
Therefore, the net work done on the object is 80 J.
An astronaut who is repairing the outside of her spaceship accidentally pushes away a 92.9 cm long steel rod, which flies off at 12.5 m/s , never to be seen again. As it happens, the rod is oriented perpendicularly to the magnetic field in that region of space. The rod is moving perpendicularly to its length as well as to the direction of the magnetic field. The magnetic field strength there is 6.23 mT . What is the magnitude of the EMF, in millivolts, induced between the ends of the rod
Answer:
V = 0.0723 volts = 72.3 milivolts
Explanation:
The emf induced in the rod is the motional emf due to the magnetic field. This motional emf can be calculated by the following formula:
[tex]EMF = V = vBl Sin\theta[/tex]
where,
V = Motional EMF = ?
v = speed of rod = 12.5 m/s
B = Magnetic Field = 6.23 mT = 0.00623 T
l = Length of rod = 92.9 cm = 0.929 m
θ = angle between v and B = 90°
Therefore,
[tex]V = (12.5\ m/s)(0.00623\ T)(0.929\ m)Sin\ 90^o\\[/tex]
V = 0.0723 volts = 72.3 milivolts