Answer:
50 m
Explanation:
The relationship between the intensity of sound in dB and distance is given by the formula:
[tex]B_2=B_1+20log(\frac{R_1}{R_2} )\\\\Where \ B_2\ is \ the\ sound\ intensity\ at\ distance\ R_2\ and\\B_1\ is \ the\ sound\ intensity\ at\ distance\ R_1\ \\\\Given\ that: B_1=100\ dB, R_1=5\ m, B_2=80\ dB\\\\B_2=B_1+20log(\frac{R_1}{R_2} )\\\\80=100+20log(\frac{5}{R_2} )\\\\-20=20log(\frac{5}{R_2} )\\\\log(\frac{5}{R_2} )=-1\\\\\frac{5}{R_2}=10^{-1}\\\\\frac{5}{R_2}=0.1\\\\R_2=5/0.1=50\ m[/tex]
It takes 3.8 x 10^-5 for a pulse of the radio waves from a radar to reach a plane and bounce back. How far is the plane from the radar?
Answer: 11400 m
Explanation:
Given:
t = 3.8 x 10^-5 s
v = 3 x 10^8 m/s
d = ?
Formula:
d = vt
= (3.8 x 10^-5 s)(3 x 10^8 m/s)
= 11400 m
hope this helps :)
The uniform movement allows to find the results for the distance from the radar to the plane is: 5.7 10³ m or 5.7 km
Kinematics studies the motion of objects looking for relationships between position, velocity and acceleration, in the special case that the acceleration is zero is called uniform motion and is described by the expression
[tex]v = \frac{d}{t}[/tex]
d = v t
Where v is the velocity, d the displacement and t the time.
Radar waves are electromagnetic waves with constant velocity
v = 3 10⁸ m/s
They indicate that the time of the waves to go to the plane and return is 3.8 10⁻⁵ s, therefore if the speed is constant, the time to reach the plane is half of the total time.
t = [tex]\frac{t_{total} }{ 2}[/tex]
t = [tex]\frac{3.8 \ 10^{-5}}{2}[/tex]
t = 1.9 10⁻⁵ s
Let's calculate
d = 3 10⁸ 1.9 10⁻⁵
d = 5.7 10³
In conclusion with the uniform movement we can find the results for the distance from the radar to the plane is: 5.7 10³ m or 5.7 km
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A cannonball is fired horizontally from a 10 m high cliff at 20 m/s. How long will the cannonball be in the air? How far away will the cannonball strike the ground?
Answe ¡Buenos días! –
#3 ¡Buenas tardes! –
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Victor has 100 trading cards, each with a distinct power level between 101 and 200 inclusive. Whenever he heads out, he always randomly selects 21 cards to bring with him just in case he meets a fellow collector. Prove that no matter which 21 cards he brings, Victor will always be able to select 4 of those cards that exhibit the following property:
Let the average power level of all 4 cards bep. The cards can be split into two pairs, each of which also has an average power level of p.
Answer:
Victor will always be able to select 4 of those cards with the following property
Explanation:
Number of trading cards = 100
victor selects 21 cards
let the 4 cards be labelled : A,B,C and D
The average power level of : A,B,C,D = ( A + B + C + D )/ 4 = P
let the two pairs be : ( A + B ) and ( C + D )
note: average power of each pair = P and this shows that
( A + B ) = ( C + D ) for Victor to select 4 cards out of the 21 cards that exhibit the same property
we have to check out the possible choices of two cards out of 21 cards yield distinct sums.
= C(21,2)=(21x20)/2 = 210.
from the question the number of distinct sums that can be created using 101 through 200 is < 210 .
hence it is impossible to get 210 distinct sums therefore Victor will always be able to select 4 of those cards
Find the linear velocity of a point moving with uniform circular motion, if the point covers a distance s in the given amount of time t. s
Answer:
The linear velocity is represented by the following expression: [tex]v = \frac{s}{t}[/tex]
Explanation:
From Rotation Physics we know that linear velocity of a point moving with uniform circular motion is:
[tex]v = r\cdot \omega[/tex] (Eq. 1)
Where:
[tex]r[/tex] - Radius of rotation of the particle, measured in meters.
[tex]\omega[/tex] - Angular velocity, measured in radians per second.
[tex]v[/tex] - Linear velocity of the point, measured in meters per second.
But we know that angular velocity is also equal to:
[tex]\omega = \frac{\theta}{t}[/tex] (Eq. 2)
Where:
[tex]\theta[/tex] - Angular displacement, measured in radians.
[tex]t[/tex] - Time, measured in seconds.
By applying (Eq. 2) in (Eq. 1) we get that:
[tex]v = \frac{r\cdot \theta}{t}[/tex] (Eq. 3)
From Geometry we must remember that circular arc ([tex]s[/tex]), measured in meters, is represented by:
[tex]s = r\cdot \theta[/tex]
[tex]v = \frac{s}{t}[/tex]
The linear velocity is represented by the following expression: [tex]v = \frac{s}{t}[/tex]
A crane uses a single cable to lower a steel girder into place. The girder moves with constant speed. The cable tension does work WT and gravity does work WG. Which statement is true
Explanation:
Work done by a force is given by :
[tex]W=Fd\cos\theta[/tex]
Where
F is force, d is displacement and [tex]\theta[/tex] is the angle between F and d.
In this problem, a crane is moving in downward direction, the force gravity is in downward direction and the tension is in upward direction.
We know that if force and displacement is in same direction, work is positive while if force and displacement is in oposite direction, work is negative.
I would mean that, [tex]W_g[/tex] is positive, because gravity is parallel to the displacement and [tex]W_t[/tex] is negative, because the tension is opposite to the displacement.
How do I proton and and electron compared
Name the part of the human eye which acts as a protective layer for the eye
Answer:
Cornea
Explanation:
Cornea protects outer layer of the eye.
Which factor affects the amount of runoff that occurs in an area?
land use
the water table
the saturation zone
amount of nutrients in soil
Answer:
A. land use
Explanation:
Answer:
a
Explanation:
What is the volume of an object if it has a mass of 10 grams and a density of 87 g/ml
Answer:
The answer is 0.115 mLExplanation:
The volume of a substance when given the density and mass can be found by using the formula
[tex]volume = \frac{mass}{density} \\[/tex]
From the question
mass = 10 g
density = 87 g/ml
We have
[tex]volume = \frac{10}{87} \\ = 0.114942528...[/tex]
We have the final answer as
0.115 mLHope this helps you
Luck walked to a store that is 250m away and it took him 50secs while Layne walked to the mall that is 1000m away and took her 200s to do. What do they have in common?
A. Average speed
B. Acceleration
C. Displacement
D.mass
Answer:
Average speed
Explanation:
250/50=5
1000/20=5
Man A (70kg) and Man B (90kg) are hanging motionless from a platform at rest. What is the tension TA in the top rope if the platform accelerates upward at a constant rate of 2 m/s2
Answer:
The tension in the upper rope (top rope), T1 = 1,888 N
Explanation:
The Parameters that were given:
Mass A, M1 = 70kg
Mass B. M2 = 90kg
acceleration, a = 2 m/s2
Assume the rope doesn't have mass, acceleration due to gravity, g
= 9.8 m/s2
The tension, T in a platform = m (a + g)
Then the tension, T1 in the upper rope = m1 (a + g) + T2
Where T2 = Tension in the lower rope
First, we calculate T2
Since the platform accelerates upward the acceleration would be positive
T2 = m2 (a + g)
T2 = 90kg ( 2 m/s2 + 9.8 m/s2)
T2 = 1,062N
To calculate the tension T1,
T1 = m1 (a + g) + T2
= 70kg (2 m/s2 + 9.8 m/s2) + 1062N
T1 = 1,888 N
distance is constant and time increseas
Will Speed increase or decrease?
Answer:
The speed will be decrease
Explain why the bottom of the ship is deeper below the surface of the sea
when the ship is fully loaded with cargo
Answer:
uhh more mass = more pull by gravity = ship go sinky more
Explanation:
Help me Please!!!!!!!
What is the speaker’s power output if the sound intensity level is 102 dBdB at a distance of 25 mm ? Express your answer to two significant figures and include the appropriate units.
Answer:
Power = 124.50 W
Explanation:
Given that:
The Sound intensity of a speaker output is 102 dB
and the distance r = 25 m
For the intensity of sound,
[tex]\beta (dB)= 10 \ log_{10 } (\dfrac{I}{I_o})[/tex]
where;
the threshold of hearing [tex]I_o = 10^{-12} (W/m^2)[/tex]
[tex]\dfrac{102 }{10}= log_{10}( \dfrac{I}{10^{-12}})[/tex]
[tex]10^{10.2} = \dfrac{I}{10^{-12}}[/tex]
[tex]I = 10^{10.2} \times 10^{-12}[/tex]
I = 0.01585 W/m²
If we recall, we know remember that ;
Power = Intensity × A rea
Power = 0.01585 W/m² × 4 × 3.142 × (25 m)²
Power = 124.50 W
Which best explains a difference between Einstein’s general theory of relativity and his special theory of relativity?
His general theory includes uniform and accelerated motion, but his special theory applies only to uniform motion.
His general theory includes uniform and accelerated motion, but his special theory applies only to accelerated motion.
His general theory applies only to accelerated motion, but his special theory includes uniform and accelerated motion.
His general theory applies only to uniform motion, but his special theory includes uniform and accelerated motion.
Answer:
His general theory includes uniform and accelerated motion, but his special theory applies only to uniform motion.
Explanation:
According to Einstein's 1915 general theory of relativity, the force of gravity arises from the curvature of space and time.
According to theory of special relativity:
1. The laws of physics are the same for all non-accelerating observers
2. The speed of light in a vacuum was independent of the motion of all observers.
His general theory includes uniform and accelerated motion, but his special theory applies only to uniform motion.
Answer:
for those who dont like to read
the answer is A.
hope i helped
Explanation:
7N
6
→ 2N
Net Force:
Determine the net force acting on the object.
Answer:
When a force is applied to the body, not only is the applied force acting, there are many other forces like gravitational force Fg, frictional force Ff and the normal force that balances the other force. Therefore, the net force formula is given by, FNet = Fa + Fg + Ff + FN.
Explanation:
A boy whirls a ball on a string in a horizontal circle of radius 1 m. How many revolutions per minute must the ball make if its acceleration towards the center of the circle is to have the same magnitude as the acceleration due to gravity
Answer:
Nearest, the revolutions per minute will be 29.
Explanation:
Given that,
Radius of circle = 1 m
Acceleration a =g
We know that,
Angular frequency is defined as,
[tex]\omega=2\pi n[/tex]
Where, n = number of revolutions in one second
We need to calculate the revolutions in one second
Using formula of centripetal acceleration
[tex]a=\omega^2r[/tex]
Put the value of a and ω
[tex]g=(2\pi n)^2r[/tex]
[tex]n=\sqrt{\dfrac{g}{r}}\times\dfrac{1}{2\pi}[/tex]
Put the value into the formula
[tex]n=\sqrt{\dfrac{9.8}{1}}\times\dfrac{1}{2\pi}[/tex]
[tex]n=0.49[/tex]
We need to calculate the revolutions per minute
Using value for the revolutions per minute
[tex]n=0.49\times60[/tex]
[tex]n=29.4[/tex]
Hence, Nearest, the revolutions per minute will be 29.
A student uses a microwave oven to heat a meal. The wavelength of the radiation is 8.97 cm. What is the energy of one photon of this microwave radiation? Multiply the answer you get by 1025 to be able to input a number more easily into canvas. Enter to 2 decimal places.
Answer:
The energy of one photon is 2.21x10⁻²⁴ J. Multiplied by 10²⁵ is 22.10 J.
Explanation:
The energy (E) of a photon is:
[tex] E = h\frac{c}{\lambda} [/tex]
Where:
h: is the Planck's constant = 6.62x10⁻³⁴ J.s
λ: is the wavelength of the radiation = 8.97 cm
c: is the speed of light = 3.00x10⁸ m/s
[tex] E = h\frac{c}{\lambda} = 6.62 \cdot 10^{-34} J.s\frac{3.00\cdot 10^{8} m/s}{8.97 \cdot 10^{-2} m} = 2.21 \cdot 10^{-24} J [/tex]
Hence, the energy of one photon is 2.21x10⁻²⁴ J.
Now, if we multiply the answer by 10²⁵ we have:
[tex] E = 2.21 \cdot 10^{-24} J \cdot 10^{25} = 22.10 J [/tex]
I hope it helps you!
The energy of one photon is 2.21x10⁻²⁴ J. Multiplied by 10²⁵ is 22.10 J.
Calculation of energy:We know that
[tex]E = h\frac{c}{\lambda}[/tex]
Here
h be the Planck's constant = 6.62x10⁻³⁴ J.s
λ be the wavelength of the radiation = 8.97 cm
c be the speed of light = 3.00x10⁸ m/s
Now
Here we need to multiply the answer 10^25 so that the correct answer could come.
[tex]E = 6.62.10^{-34} \frac{3.00.10^{8}}{8.97.10^{-2}}[/tex]
= 2.21x10⁻²⁴ J.
= 22.10 J.
Hence, the energy of one photon is 2.21x10⁻²⁴ J. Multiplied by 10²⁵ is 22.10 J.
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Please help me with this!
hope this helps good luck
A bird is flying in a room with a velocity field of . Calculate the temperature change that the bird feels after 9 seconds of flight, as it flies through x
Complete Question
The complete question is shown on the first uploaded image
Answer:
The temperature change is [tex]\frac{dT}{dt} = 1.016 ^oC/m[/tex]
Explanation:
From the question we are told that
The velocity field with which the bird is flying is [tex]\vec V = (u, v, w)= 0.6x + 0.2t - 1.4 \ m/s[/tex]
The temperature of the room is [tex]T(x, y, u) = 400 -0.4y -0.6z-0.2(5 - x)^2 \ ^o C[/tex]
The time considered is t = 10 \ seconds
The distance that the bird flew is x = 1 m
Given that the bird is inside the room then the temperature of the room is equal to the temperature of the bird
Generally the change in the bird temperature with time is mathematically represented as
[tex]\frac{dT}{dt} = -0.4 \frac{dy}{dt} -0.6\frac{dz}{dt} -0.2[2 * (5-x)] [-\frac{dx}{dt} ][/tex]
Here the negative sign in [tex]\frac{dx}{dt}[/tex] is because of the negative sign that is attached to x in the equation
So
[tex]\frac{dT}{dt} = -0.4v_y -0.6v_z -0.2[2 * (5-x)][ -v_x][/tex]
From the given equation of velocity field
[tex]v_x = 0.6x[/tex]
[tex]v_y = 0.2t[/tex]
[tex]v_z = -1.4 [/tex]
So
[tex]\frac{dT}{dt} = -0.4[0.2t] -0.6[-1.4] -0.2[2 * (5-x)][ -[0.6x]][/tex]
substituting the given values of x and t
[tex]\frac{dT}{dt} = -0.4[0.2(10)] -0.6[-1.4] -0.2[2 * (5-1)][ -[0.61]][/tex]
[tex]\frac{dT}{dt} = -0.8 +0.84 + 0.976[/tex]
[tex]\frac{dT}{dt} = 1.016 ^oC/m[/tex]
Which of the following is the closest to the scientific fact
A. A hypothesis
B. A theory
C. An opinion
D. A prediction
A theory is the closest to a scientific fact (Option B).
A scientific theory is a well-sustained scientific idea that has been verified using the scientific method.A scientific theory can be refuted by the emergence of new lines of evidence against some aspect of this scientific statement.A hypothesis is a given explanation about a question that emerged by observing the natural world.In conclusion, a theory is the closest to a scientific fact (Option B).
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How many turns are in its secondary coil, if its input voltage is 120 V and the primary coil has 210 turns
Complete Question
How many turns are in its secondary coil, if its input voltage is 120 V and the primary coil has 210 turns.
The output from the secondary coil is 12 V
Answer:
The value is [tex]N_s = 21 \ turns [/tex]
Explanation:
From the equation we are told that
The input voltage is [tex]V_{in} = 120 \ V[/tex]
The number of turns of the primary coil is [tex]N_p = 210 \ turn[/tex]
The output from the secondary is [tex]V_o = 12V[/tex]
From the transformer equation
[tex]\frac{N_p}{V_{in}} =\frac{N_s}{V_o}[/tex]
Here [tex]N_s[/tex] is the number of turns in the secondary coil
=> [tex]N_s = \frac{N_p}{V_{in}} * V_s[/tex]
=>[tex]N_s = \frac{210}{120} * 12[/tex]
=>[tex]N_s = 21 \ turns [/tex]
A vector of components (−23, −22) is multiplied by the scalar value of −6. What is the magnitude and direction of the resultant vector?
Answer:
(1,)
Explanation:
Answer:
magnitude: 21.6; direction: 33.7°
Explanation:
Six seconds after starting from rest, a car is moving at 15 m/s. What is the car's
average acceleration?
6 m/s2
0-5 m/s?
5 m/s2
2.5 m/s?
-2.5 m/s?
Answer:
2.5 m/s²
Explanation:
a = ∆v/∆t = (15 m/s)/(6 s) = (15/6) m/s² = 2.5 m/s²
please help asap
You jog for 55 minutes and reach a park that is 4.8 km away. What was your speed?
Answer: 59.8 or 299/5- 55 x 4.8=264
Explanation:
Or if you wish to multiply it then the answer is above with the addition version.
Hope this helped :)
Engineers are using computer models to study train collisions to design safer
train cars. They start by modeling an elastic collision between two train cars
traveling toward each other. Car 1 is traveling north at 20 m/s and has a mass
of 12,745 kg. Car 2 is traveling south at 15 m/s and has a mass of 4,125 kg.
After the collision, car 1 has a final velocity of 3 m/s north. What is the final
velocity of car 2?
A. 56 m/s north
B. 56 m/s south
C. 38 m/s south
D. 38 m/s north
Answer:
did you get the answer???
Answer: 38 m/s north
Explanation:
1. What quantity of heat is required to raise?
the temperature of 450 grams of water
from 35°C to 85°C?
capacity of water is 4.18 J/g °C.
Answer: Calculate the energy required in joules to raise the temperature of 450 grams of water from 15°C to 85°C? (The specific heat capacity of water is 4.18 J/g/°C)
Explanation:
The quantity of heat is required to raise the temperature of of water is 94050 joule.
What is law of conservation of energy?Energy cannot be created or destroyed, according to the law of conservation of energy. However, it is capable of change from one form to another. An isolated system's total energy is constant regardless of the types of energy present.
The law of energy conservation is adhered to by all energy forms. The law of conservation of energy essentially says that the total energy of the system is conserved in a closed system, also known as an isolated system.
Mass of water: m = 450 grams
Initial temperature of water = 35° C
Final temperature of water = 85° C
Capacity of water is 4.18 J/g °C.
Hence, the quantity of heat is required to raise = mass × Capacity × raise in temperature
= 450 × 4.18 × (85 - 35) joule
= 94050 joule.
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what phase changes take place when you are adding energy to the substance
Answer:
During a phase change, a substance undergoes transition to a higher energy state when heat is added, or to a lower energy state when heat is removed. Heat is added to a substance during melting and vaporization. Latent heat is released by a substance during condensation and freezing. Explanation:
For an answer to be complete the units need to be specified.why?