When two waves collide and create a taller wave, what interference occurs?
1 answer:
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Answer:
The magnitude of the friction force exerted on the box is 2.614 newtons.
Explanation:
Since the box is sliding on a rough horizontal floor, then it is decelerated solely by friction force due to the contact of the box with floor. The free body diagram of the box is presented herein as attachment. The equation of equilbrium for the box is:
(Eq. 1)
Where:
- Kinetic friction force, measured in newtons.
- Mass of the box, measured in kilograms.
- Acceleration experimented by the box, measured in meters per square second.
By applying definitions of weight () and uniform accelerated motion (
), we expand the previous expression:
And the magnitude of the friction force exerted on the box is calculated by this formula:
(Eq. 1b)
Where:
- Weight, measured in newtons.
- Gravitational acceleration, measured in meters per square second.
- Initial speed, measured in meters per second.
- Final speed, measured in meters per second.
- Time, measured in seconds.
If we know that ,
,
,
and
, the magnitud of the kinetic friction force exerted on the box is:
The magnitude of the friction force exerted on the box is 2.614 newtons.
Answer:
distance is 13 m for 100 dB
distance is 409 km for 10 dB
Explanation:
Given data
distance r = 2.30 m
source β = 115 dB
to find out
distance at sound level 100 dB and 10 dB
solution
first we calculate here power and intensity and with this power and intensity we will find distance
we know sound level β = 10 log(I/) ......................a
put here value (I/) = 10^−12 W/m² and β = 115
115 = 10 log(I/10^−12)
so
I = 0.316228 W/m²
and we know power = intensity × 4π r² ...............b
power = 0.316228 × 4π (2.30)²
power = 21.021604 W
we know at 100 dB intensity is 0.01 W/m²
so by equation b
power = intensity × 4π r²
21.021604 = 0.01 × 4π r²
so by solving r
r = 12.933855 m = 13 m
distance is 13 m
and
at 10 dB intensity is 1 × 10^–11 W/m²
so by equation b
power = intensity × 4π r²
21.021604 = 1 × 10^–11 × 4π r²
by solving r we get
r = 409004.412465 m = 409 km