Which of the statements concerning light are true? The speed of light is the same no matter what material it is traveling throug
1 answer:
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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
Answer:
Fc = 19.2 N
Explanation:
In this case, the force of the Honda over the rock, is a centripetal force. Then, you have:
m: mass of the rock = 600g = 0.6 kg
v: tangential velocity of the Honda = 4m/s
r: radius of the Honda = 50cm = 0.5m
You replace the values of m, r and v in the equation for Fc:
hence, the force has a magnitude of 19.2 N
If the rock would have more mass the centripetal force would be higher
