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Aleksandr-060686 [28]

2 years ago

10

The speed of sound in dry air at 20 °C is 343.5 m s-1, and the frequency of the sound from the note C# above middle C on the pia

no is 277.2 s-1(according to the American standard pitch scale). Calculate the wavelength of the sound and the time it will take to travel 49.2 m across a concert hall. Wavelength = (answer) m

1 answer:

Nastasia [14]2 years ago

4 0

Answer:

1.23917 m

0.14323 s

Explanation:

v = Speed of sound in dry air at 20 °C = 343.5 m/s

f = Frequency of note C# = 277.2 /s = 277.2 Hz

λ = Wavelength

$v=f\lambda\\\Rightarrow \lambda=\frac{v}{f}\\\Rightarrow \lambda=\frac{343.5}{277.2}\\\Rightarrow \lambda=1.23917\ m$

Wavelength = 1.23917 m

Distance the wave needs to travel is 49.2 m

Time = Distance / Speed

$\text{Time}=\frac{49.2}{343.5}=0.14323\ s$

Time taken for the sound to travel across the concert hall is 0.14323 s

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A satellite is in circular orbit at an altitude of 1500 km above the surface of a nonrotating planet with an orbital speed of 9.

Ksju [112]

To solve this problem we will use the Newtonian theory about the speed of a body in space for which the speed of a body in the orbit of a planet is summarized as:

$v = \sqrt{\frac{2GM}{R}}$

Where,

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M = Mass of Planet

r = Radius of the planet ('h' would be the orbit from the surface)

The escape velocity is

$v = 14.9km/h = 14900m/s$

Through this equation we can find the mass of the Planet in function of the distance, therefore

$M = \frac{v^2R}{2G}$

$M = \frac{14900^2R}{2(6.67*10^{-11})}$

$M = 16.64*10^{17}R$

The orbital velocity is

$v_o = \sqrt{\frac{GM}{R+h}}$

$9200^2 = \frac{(6.67*10^{-11})(16.64*10^{17})R}{R+1500*10^3}$

$11.1*10^7R = (R+15000*10^3)(9200)^2$

$2.64*10^7R = 12.69*10^{13}$

$R = 4.81*10^6m$

The time period of revolution is,

$T = \frac{2\pi(R+h)}{v_o}$

$T = \frac{2\pi(4.81*10^6+1.5*10^6)}{9200}$

$T = 4307s$

$T = 72min = 1hour12min$

Therefore the orbital period of the satellite is closes to 1 hour and 12 min

3 0

1 year ago

The top floor of the Ostankino TV Tower in Moscow is located at a height of 360.4 m. Assume a stone is dropped from this top flo

Ulleksa [173]

Answer:

$x=360.4-4.905t^2$

8.57181 s

84.0894561 m/s

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

g = Acceleration due to gravity = 9.81 m/s² = a

Let distance from ground be x

From equation of motion we have

$s=ut+\frac{1}{2}at^2$

Here, distance covered while the stone is falling will be $360.4-x$

$360.4-x=ut+\frac{1}{2}at^2\\\Rightarrow 360.4-x=\frac{1}{2}9.81t^2\\\Rightarrow 360.4-x=4.905t^2\\\Rightarrow x=360.4-4.905t^2$

The equation is $x=360.4-4.905t^2$

At the ground x = 0

$0=360.4-4.905t^2\\\Rightarrow t=\sqrt{\dfrac{-360.4}{-4.905}}\\\Rightarrow t=8.57181\ s$

The time taken by the stone to fall to the ground is 8.57181 s

$v=u+at\\\Rightarrow v=0+9.81\times 8.57181\\\Rightarrow v=84.0894561\ m/s$

The velocity of the stone when it reaches the ground is 84.0894561 m/s

8 0

2 years ago

What charge accumulates on the plates of a 2.0-μF air-filled capacitor when it is charged until the potential difference across

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Answer:

0.0002 C.

Explanation:

Charge: This can be defined as the ratio of current to time flowing in a circuit. The S.I unit of charge is Coulombs (C)

Mathematically, charge can be expressed as

Q = CV ................................. Equation 1

Where Q = amount of charge, C = capacitance of the capacitor, V = potential difference across the plates.

Given: C = 2.0-μF = 2×10⁻⁶ F, V = 100 V.

Substitute into equation 1

Q = 2×10⁻⁶× 100

Q = 2×10⁻⁴ C

Q = 0.0002 C.

The amount of charge accumulated = 0.0002 C

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1 year ago

Read 2 more answers

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Answer:

Since the stopping distance is less than the thinking distance, Mr Hoyland is therefore responsible for the accident

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3. The reaction time of a drunk driver could be 2s.

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6. From the time of applying the brakes the total braking distance in bad

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1. Calculate the thinking distance for a car travelling at 30m/s

2. Calculate the braking distance for a car travelling in normal conditions at 30m/s

3. Calculate the total stopping distance.

4. REMEMBER TO SHOW YOUR WORKING OUT

Challenge:

1. Is Mr Hoyland responsible for the accident?

2. Explain your answer giving CLEAR reasons for your answer and likely causes.

The Thinking distance = 100m

The breaking distance = 70m

A breaking distance = Stopping distance = 70m

Since the stopping distance is less than the thinking distance, Mr Hoyland is therefore responsible for the accident

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Law Incorporation [45]

Answer B

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