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enyata [817]
3 years ago
3

While the decibel scale can be used in many disciplines, we shall restrict our attention to its use in acoustics, specifically i

ts use in measuring the intensity level of sound. The Sound Intensity Level (measured in decibels) of a sound intensity (measured in watts per square meter) is given by Compute Damage to your hearing can start with short term exposure to sound levels around 115 decibels. What intensity is needed to produce this level
Physics
1 answer:
Xelga [282]3 years ago
3 0

Answer:

I = 0.316 W/m^2

Explanation:

In order to calculate the intensity required to produce a sound level of 115 decibels, you use the following formula:

B=10log(\frac{I}{I_o})   (1)

B: sound level = 115dB

I: intensity of the sound = ?

Io: Threshold of hearing = 10^-12 W/m^2

You solve the equation (1) for I, by using properties of logarithms:

B=log(\frac{I}{I_o})^{10}\\\\10^{B}=10^{log(\frac{I}{I_o})^{10}}\\\\10^B=(\frac{I}{I_o})^{10}\\\\I=I_o10^{B/10}

Finally, you replace the values of all parameters:

I=(10^{-12}W/m^2)10^{115/10}\\\\I=0.316\frac{W}{m^2}

The intensity that produces a sound level of 115 dB is 0.316 W/m^2

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Suppose that a 1000 kg car is traveling at 25 m/s (aprox 55mph). Its brakes can apply a force of 5000N. What is the minimum dist
Brrunno [24]

Assuming the the car is travelling to the right (→):

R(\rightarrow), F = ma

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=  \frac{-5000}{1000}

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u = 25 \ ms^{-1}

v = 0

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A 0.676 m long section of cable carrying current to a car starter motor makes an angle of 57.7º with the Earth’s 5.29 x 10^−5T f
Studentka2010 [4]

Answer:

The current in the wire under the influence of the force is 216.033 A

Solution:

According to the question:

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\theta = 57.7^{\circ}

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Forces experienced by the wire, F_{m} = 6.53\times 10^{-3} N

Also, we know that the force in a magnetic field is given by:

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3 years ago
A jet plane is flying at a constant altitude. At time t1 = 0, it has components of velocity vx = 90 m/s, vy = 110 m/s. At time t
Vika [28.1K]

Answer:

a) See attachment.

b) a_avg = -8.66 i - 2.33 j

c) a = 195 degrees from + x-axis.  |a_avg| = 8.97 m/s^2

Explanation:

Given:

- Initial Velocity V_i = (90 i + 110 j)

- Final velocity V_f = (-170 i + 40 j)

- t_i = 0

- t_f = 30.0 s

Find:

(a) Sketch the velocity vectors at t1 and t2. How do these two vectors differ?

(b) the components of the average acceleration

(c) the magnitude and direction of the average acceleration.

Solution:

- The change in velocity is given by:

                            Δ V = (V_f - V_i)

                            Δ V = ( -170 i - 90 i + 40 j - 110 j)

                            Δ V = (-260 i - 70 j)

- The change in time is given as:

                            Δ t = t_f - t_i = 30 - 0 = 30 s

-The average acceleration is:

                            a_avg = Δ V / Δ t

                            a_avg = (-260 i - 70 j) / 30

                           a_avg = -8.66 i - 2.33 j

- The magnitude of acceleration is:

                            |a_avg| = sqrt ( 8.66^2 + 2.33^2)

                            |a_avg| = sqrt (80.4245)

                            |a_avg| = 8.97 m/s^2

- The direction of acceleration is given by:

                            tan (Q) = a_y / a_x

                            Q = arctan(a_y / a_x)

                            Q = arctan(2.33 / 8.66)

                            Q = 15 degrees

Hence, 180 + 15 = a.        a = 195 degrees from + x-axis.

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What is the speed of the pulley A if pully D is moving at a speed of 8 km/h​
Serhud [2]

Answer:

hey I know the answer for this

Explanation:

it will be reduce the speed of A

the answer is 7.

this is the exact answer.

if you don't like this answer means pls comment me

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