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Mila [183]
3 years ago
12

A sound source emits 20.0 W of acoustical power spread equally in all directions. The threshold of hearing is 1.0 × 10-12 W/m2.

C_9. What is the sound intensity 30.0 m (in W/m2 ) from the source?
Physics
1 answer:
ahrayia [7]3 years ago
7 0

Answer:

0.0018 W/m²

Explanation:

Power and intensity are related as:

I=\frac{P}{4\pi r^2}

P=  20.0 W (given)

r = 30.0 m (given)

I=\frac{20.0}{4\pi(30.0)^2}=0.0018 W/m^2

Intensity in decibels:

I(dB)=10log\frac{I}{I_o}\\=10log\frac{0.0018}{10^{-12}}=92.5 dB

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A(n) 93 kg clock initially at rest on a horizontal floor requires a(n) 610 N horizontal force to set it in motion. After the clo
denpristay [2]

Answer:0.669

Explanation:

Given

mass of clock 93 kg

Initial force required to move it 610 N

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Initially static friction is acting which is more than kinetic friction

thus 613 force is required to overcome static friction

\mu _smg=610

\mu _s\times 93\times 9.8=610

\mu _s=0.669

5 0
3 years ago
You want to place a mirror at a blind turn on the staircase in your house. Which would be best suited for this purpose?
Eduardwww [97]
You can't see beyond a blind turn, so a mirror would allow you to see around the corner.
6 0
3 years ago
Total potential and kinetic energy of an object.
Ne4ueva [31]

Answer:

The Total Mechanical Energy

As already mentioned, the mechanical energy of an object can be the result of its motion (i.e., kinetic energy) and/or the result of its stored energy of position (i.e., potential energy). The total amount of mechanical energy is merely the sum of the potential energy and the kinetic energy.

Explanation:

8 0
3 years ago
a shell fired from a cannon at 60 ° from horizontal strikes a target 20m high at a distance 80m. Calculate the initial velocity
stich3 [128]

consider the motion along the X-direction

X = horizontal displacement = 80 m

V_{ox} = initial velocity along the x-direction = v Cos60

t = time of travel

using the equation

X = V_{ox}   t

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t = 160/v                                         eq-1


consider the motion in vertical direction :

Y = vertical displacement = 20 m

V_{oy}  = initial velocity in Y-direction = v Sin60

a = acceleration = - 9.8 m/s²

t = time of travel = 160/v

using the equation

Y = V_{oy}  t + (0.5) a t²

20 = (v Sin60) (160/v) + (0.5) (- 9.8) (160/v)²

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4 0
3 years ago
A 0.49-kg cord is stretched between two supports, 7.8m apart. When one support is struck by a hammer, a transverse wave travels
katovenus [111]

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v = \sqrt{\frac{T}{\mu}}

Here,

v = Velocity

\mu= Linear density (Mass per  unit length)

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As we know that speed is equivalent to displacement in a unit of time, we will have to

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T = (\frac{7.8}{0.83})^2 (\frac{0.49}{7.8})

T = 5.54N

Therefore the tension is 5.54N

8 0
3 years ago
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