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ikadub [295]
3 years ago
13

Sound is more effectively transmitted into a stethoscope by direct contact than through the air, and it is further intensified b

y being concentrated on the smaller area of the eardrum. It is reasonable to assume that sound is transmitted into a stethoscope 100 times as effectively compared with transmission though the air. What, then, is the gain in decibels produced by a stethoscope that has a sound gathering area of 15.0 cm2, and concentrates the sound onto two eardrums with a total area of 1.00 cm2 with an efficiency of 37.0%?

Physics
1 answer:
GrogVix [38]3 years ago
5 0

Answer:

Δβ = 28.2 dB

Explanation:

Attached is the explanation

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2. A Se lanza un electrón con rapidez inicial v0 = 1.60×106 m/s hacia el interior de un campo uniforme entre las placas paralela
Vanyuwa [196]

Answer:

A)     E = 145.6 N / C , B)  y= 2,8 10-7 m with a downward direction

C) he shape of the trajectory of the two particles is to simulate a parabola,

D)     F_{e} /F_{g} = 10³⁴

Explanation:

A) For this exercise we use Newton's second law to find the acceleration of the electron, where the force is electric

           F = m a  

           - e E = m a

          a = - e E / m

with the field directed downward, the acceleration is in the vertical upward direction.

We look for how much the electron moves with kinematics, in the x direction there is no acceleration,

x axis (parallel to plates)

           x = v₀ t

           t = x / v₀

y axis (perpendicular to plates)

          y = y₀ + v_{oy} t + ½ a t²

Let's take the zero of the system in the middle of the plates y₀ = 0, also the initial vertical velocity is zero (v_{oy} = 0) the width of the plate is known

          y = ½ a t²

we substitute

         y = ½ (e E /m)  (x / v₀)²

         y = ½ e x2 /m v₀²   E

we look for the electric field

        E = 2 m y v₀² / e x²

where to use this expression the length and width of the condenser must be known, suppose that the length is x = l = 1 cm = 1 10⁻² m and the width is y = 0.5 mm = 0.5 10⁻³ m

let's calculate

         E = 2  9.1 10⁻³¹ 0.5 10⁻³ (1.6 10⁶)² / (1.6 10⁻¹⁹ (1 10⁻²)²)

         E = 145.6 N / C

B) The electron is exchanged for a proton

Let's look for the vertical displacement, in this case as the proton has a positive charge it moves towards the bottom of the plates

          y = ½ e x² / m v₀² E

          y = ½ 1.6 10⁻¹⁹ 1 10⁻⁴ / (1.67 10⁻²⁷ (1.6 10⁶)²   145.6

          y = 28.4375 10⁻⁸ m

since the distance between the plates is 0.5 10-3 m, the proton passes the condensate because its deflection is very small

In summary, its displacement is y= 2,8 10-7 m and with a downward direction (the same direction of the electric field)

C) The shape of the trajectory of the two particles is to simulate a parabola, but one for having a negative charge (electron) the force is upwards and the other for having a positive charge (proton) the trajectory is downwards

D) The force of gravity

           F_{g} = G m M / R²

electron

          Between the electron and the positive charges of the conducting plate

           F_{g}= 6.67 10⁻¹¹ 1.67 10⁻²⁷ 9.1 10⁻³¹ / (0.5 10⁻³)²

           F_{g} = 4.1 10⁻⁵¹ N

           

electric force

           F_{e} = -e E

           F_{e} = - 1.6 10⁻¹⁹ 145.6

           F_{e} = 2.3 10⁻¹⁷ N

let's look for the reason between these two forces

         F_{e} / F_{g} = 2.3 10⁻¹⁷ / 4.1 10⁻⁵¹

          F_{e} /F_{g} = 10³⁴

We see that the electric force is many orders of magnitude higher than the gravitational force.

5 0
3 years ago
Just say the letter of answer asap
kap26 [50]

answer  for number nine is C

Convergent boundaries: where two plates are colliding. Subduction zones occur when one or both of the tectonic plates are composed of oceanic crust.

Divergent boundaries – where two plates are moving apart. ...


Transform boundaries – where plates slide passed each other.

answer for number eight is d.

hope this help you

3 0
3 years ago
Read 2 more answers
What study did james e hansen focus on
Brut [27]
James E. Hansen studied climate change
6 0
1 year ago
Read 2 more answers
if a gas has a gage pressure of 156 kpa its absolute pressure is approximately .....A... 56 kPa ....B....100 kPa.......C......25
NeX [460]

256 kPa because p-guage + p-absolute + p-atmospheric = 256

7 0
3 years ago
Two rigid rods are oriented parallel to each other and to the ground. The rods carry the same current in the same direction. The
IRISSAK [1]

To develop this problem we will apply the concepts related to the Electromagnetic Force. The magnetic force can be defined as the product between the free space constant, the current (of each cable) and the length of these, on the perimeter of the cross section, in this case circular. Mathematically it can be expressed as,

F= \frac{\mu_0}{2\pi} \frac{I^2L}{d}

Here,

\mu_0 = Permeability free space

I = Current

L = Length

d= Distance between them

Our values are,

L = 0.67m

m = 0.082kg

d = 7.4*10^{-3}m

I = \text{Current through each of the wires}

Rearranging the previous equation to find the current,

\frac{mg}{L} = 2*10^{-7} (\frac{I^2}{d})

I = \sqrt{\frac{mgd}{(2*10^{-7})L}}

I = \sqrt{\frac{(0.082)(9.8)(7.4*10^{-3})}{(2*10^{-7})(0.67)}}

I = \sqrt{44377.9}

I = 210.66A

Therefore the current in the rods is 210.6A

8 0
3 years ago
Read 2 more answers
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