1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Inga [223]
3 years ago
8

A person wears a hearing aid that uniformly increases the sound level of all audible frequencies of sound by 28.1 dB. The hearin

g aid picks up sound having a frequency of 250 Hz at an intensity of 3.30 10-11 W/m2. What is the intensity delivered to the eardrum?
Physics
1 answer:
ladessa [460]3 years ago
4 0

Answer:

 I₂ = 2.13 x 10⁻⁸ W/m²

Explanation:

given,

increase in sound level = 28.1 dB

frequency of the sound = 250 Hz

intensity = 3.3 x 10⁻¹¹ W/m²

Intensity delivered = ?

the difference of intensity level is give as

\beta_2-\beta_1 = 10log(\dfrac{I_2}{I_o}) - 10log(\dfrac{I_1}{I_o})

\beta_2-\beta_1 = 10(log(\dfrac{I_2}{I_o}) -log(\dfrac{I_1}{I_o}))

\beta_2-\beta_1 = 10(log(\dfrac{I_2}{I_1})

28.1= 10(log(\dfrac{I_2}{I_1})

log\dfrac{I_2}{I_1}=2.81

\dfrac{I_2}{I_1}=10^{2.81}

 I₂ = 645.65 I₁

 I₂ = 645.65 x 3.3 x 10⁻¹¹

 I₂ = 2.13 x 10⁻⁸ W/m²

You might be interested in
a 230 kg roller coaster reaches the top of the steepest hill with a speed of 6.2 km/h. It then descends the hill, which is at an
igor_vitrenko [27]

Answer: 81.619 kJ

Explanation:

Given

Mass of roller coaster is m=230\ kg

It reaches the steepest hill with speed of u=6.2\ km/h\ or \ 1.72\ m/s

Hill to bottom is 51 m long with inclination of 45^{\circ}

Height of the hill is h=51\sin 45^{\circ}=36.06\ m

Conserving energy to get kinetic energy at bottom

Energy at top=Energy at bottom

\Rightarrow K_t+U_t=K_b+U_b\\\Rightarrow \dfrac{1}{2}mu^2+mgh=K_b+0\\\\\Rightarrow K_b=0.5\times 230\times 1.72^2+230\times 9.8\times 36.06\\\Rightarrow K_b=340.216+81,279.24\\\Rightarrow K_b=81,619.456\ J\\\Rightarrow K_b=81.619\ kJ

8 0
2 years ago
A child goes down the slide,starting from rest. If the length of the slide is 2m and it takes the child 3 seconds to go down the
lapo4ka [179]

Answer:

0.44 m/s^2

Explanation:

We have the following data:

- distance covered by the child: d = 2 m (length of the slide)

- time taken to cover this distance: t = 3 s

- initial velocity of the child: 0 m/s (he starts from rest)

So we can find the acceleration by using the equation:

d=ut+\frac{1}{2}at^2

Where a is the acceleration.

Substituting the values and solving for a,

a=\frac{2d}{t^2}=\frac{2(2)}{3^2}=0.44 m/s^2

3 0
3 years ago
For a damped simple harmonic oscillator, the block has a mass of 1.2 kg and the spring constant is 9.8 N/m. The damping force is
ArbitrLikvidat [17]

Answer:

a) t=24s

b) number of oscillations= 11

Explanation:

In case of a damped simple harmonic oscillator the equation of motion is

m(d²x/dt²)+b(dx/dt)+kx=0

Therefore on solving the above differential equation we get,

x(t)=A₀e^{\frac{-bt}{2m}}cos(w't+\phi)=A(t)cos(w't+\phi)

where A(t)=A₀e^{\frac{-bt}{2m}}

 A₀ is the amplitude at t=0 and

w' is the angular frequency of damped SHM, which is given by,

w'=\sqrt{\frac{k}{m}-\frac{b^{2}}{4m^{2}} }

Now coming to the problem,

Given: m=1.2 kg

           k=9.8 N/m

           b=210 g/s= 0.21 kg/s

           A₀=13 cm

a) A(t)=A₀/8

⇒A₀e^{\frac{-bt}{2m}} =A₀/8

⇒e^{\frac{bt}{2m}}=8

applying logarithm on both sides

⇒\frac{bt}{2m}=ln(8)

⇒t=\frac{2m*ln(8)}{b}

substituting the values

t=\frac{2*1.2*ln(8)}{0.21}=24s(approx)

b) w'=\sqrt{\frac{k}{m}-\frac{b^{2}}{4m^{2}} }

w'=\sqrt{\frac{9.8}{1.2}-\frac{0.21^{2}}{4*1.2^{2}}}=2.86s^{-1}

T'=\frac{2\pi}{w'}, where T' is time period of damped SHM

⇒T'=\frac{2\pi}{2.86}=2.2s

let n be number of oscillations made

then, nT'=t

⇒n=\frac{24}{2.2}=11(approx)

8 0
3 years ago
Why is cheese only strechy when its hot not when its cold (i spelt stretchy wrong but i dont want to change it cuz that would ta
IgorC [24]
That is a really good question, cheese is stretchy when it is hot is because when you heat it up, it liquefies which makes it stretch. it doesn't stretch when it is cold because it is a solid and solids usually do not stretch.
8 0
2 years ago
The weight of an objects can be calculated by multiplying mass by
Lana71 [14]
Acceleration due to gravity. 
7 0
2 years ago
Read 2 more answers
Other questions:
  • The half-life of a radioisotope is 6.0 hours. Approximately how long will it take for the activity of a sample to be reduced by
    14·1 answer
  • Suppose the roller-coaster car in fig.6–41 passes point 1 with a speed of if the average force of friction is equal to 0.23 of i
    5·1 answer
  • A particle travels along the x-axis in such a way that its acceleration at time t is a(t) = t + t2. if it starts at the origin w
    14·1 answer
  • Water ia boled at 1 at pressure in a coffe aker equpped with an immension-type electric heating element. The coffee maker intial
    10·1 answer
  • Which type of wave is allowing you to read this test question?
    12·1 answer
  • A vector A has components Ax = −4.00 m and Ay = 3.50 m. Find the magnitude (in m) and the direction (in degrees counterclockwise
    6·1 answer
  • * An 10 kg box is sitting on a fairly smooth surface. Friction is still present. The coefficient of static friction
    7·1 answer
  • Describe how the series and parallel circuits are different in terms of the direction the electrons flow in the circuit.
    15·1 answer
  • Explain the concept of energy conversion as applied to the generation of electricity also known as electrical energy.​
    9·1 answer
  • Which type of mixture is it, if the solid settles out of the mixture over time?.
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!