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I am Lyosha [343]
3 years ago
7

You watch a distant lady driving nails into her front porch at a regular rate of 1 stroke per second. You hear the sound of the

blows exactly synchronized with the blows you see. And then you hear one more blow after you see her stop hammering. How far away is she? The speed of sound is 340 m/s. a) 270 m. b) 680 m. c) 85 m. d) 1360 m. e) 170 m.
Physics
2 answers:
Evgen [1.6K]3 years ago
5 0

Answer:

The distance of the lady is 340 m

Solution:

As per the question:

Regular rate of stroke = 1 stroke per second

Speed of sound, v = 340 m/s

Now,

To calculate the distance of the lady, we need to calculate the wavelength of the sound wave which provides the distance.

Now, we know that:

v = \nu\times \lambda

where

\nu = frequency in Hz

\lambda = wavelength in meter

Also, we know that 1 stroke per second makes a frequency of 1 Hz

Thus

340 = 1\times \lambda

\lambda = 340\ m

Igoryamba3 years ago
4 0

Answer:

λ = 1360 m

Explanation:

Given data:

frequency of driving nails is given as 1 stroke per second mean at every 0.25 sec she hit the nails

speed of sound is given as 340 m/s

we know that the wave equation is given as

Speed = frequency × wavelength,

v = f × λ

where,

v = speed in meters/second (m/s)

f = frequency in Hertz (Hz)

substituing value to get wavelength  of her driving nails

340 m/s = (1Hz)\times  \lambda

\lambda = \frac{340}{0.25}

λ = 1360 m

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Answer: 56.72 ft/s

Explanation:

Ok, initially we only have potential energy, that is equal to:

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we solve it for v.

v = √(2g*h) = √(2*32.17*50) ft/s = 56.72 ft/s

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3 years ago
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Sindrei [870]

Answer with Explanation:

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alexandr1967 [171]

Answer:

The electric field strength inside the capacitor is 49880.77 N/C.

Explanation:

Given:

Side length of the capacitor plate (a) = 4.19 cm = 0.0419 m

Separation between the plates (d) = 0.407 mm = 0.407\times 10^{-3}\ m

Energy stored in the capacitor (U) = 7.87\ nJ=7.87\times 10^{-9}\ J

Assuming the medium to be air.

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Area of the square plates is given as:

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Capacitance of the capacitor is given as:

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Rewriting in terms of 'E', we get:

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Now, plug in the given values and solve for 'E'. This gives,

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