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
They circulate blood and oxygen throughout your body
Answer:
![v\approx 16.956\,\frac{m}{s}](https://tex.z-dn.net/?f=v%5Capprox%2016.956%5C%2C%5Cfrac%7Bm%7D%7Bs%7D)
Explanation:
The motion of the vehicule on a highway curve can be modelled by the following equation of equilibrium:
![\Sigma F = f = m\cdot \frac{v^{2}}{R}](https://tex.z-dn.net/?f=%5CSigma%20F%20%3D%20f%20%3D%20m%5Ccdot%20%5Cfrac%7Bv%5E%7B2%7D%7D%7BR%7D)
The maximum speed is:
![v = \sqrt{\frac{f\cdot R}{m} }](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B%5Cfrac%7Bf%5Ccdot%20R%7D%7Bm%7D%20%7D)
![v = \sqrt{\frac{(7500\,N)\cdot (46\,m)}{1200\,kg} }](https://tex.z-dn.net/?f=v%20%3D%20%5Csqrt%7B%5Cfrac%7B%287500%5C%2CN%29%5Ccdot%20%2846%5C%2Cm%29%7D%7B1200%5C%2Ckg%7D%20%7D)
![v\approx 16.956\,\frac{m}{s}](https://tex.z-dn.net/?f=v%5Capprox%2016.956%5C%2C%5Cfrac%7Bm%7D%7Bs%7D)
Assuming the accleration applied was constant, we have
![v=v_0+at\implies v_0+20.0\,\dfrac{\mathrm m}{\mathrm s}=v_0+a(0.10\,\mathrm s)](https://tex.z-dn.net/?f=v%3Dv_0%2Bat%5Cimplies%20v_0%2B20.0%5C%2C%5Cdfrac%7B%5Cmathrm%20m%7D%7B%5Cmathrm%20s%7D%3Dv_0%2Ba%280.10%5C%2C%5Cmathrm%20s%29)
![\implies20.0\,\dfrac{\mathrm m}{\mathrm s}=a(0.10\,\mathrm s)](https://tex.z-dn.net/?f=%5Cimplies20.0%5C%2C%5Cdfrac%7B%5Cmathrm%20m%7D%7B%5Cmathrm%20s%7D%3Da%280.10%5C%2C%5Cmathrm%20s%29)
![\implies a=200\,\dfrac{\mathrm m}{\mathrm s^2}](https://tex.z-dn.net/?f=%5Cimplies%20a%3D200%5C%2C%5Cdfrac%7B%5Cmathrm%20m%7D%7B%5Cmathrm%20s%5E2%7D)
Then the force applied to the ball is given by
![F=ma=(0.45\,\mathrm{kg})\left(200\,\dfrac{\mathrm m}{\mathrm s^2}\right)](https://tex.z-dn.net/?f=F%3Dma%3D%280.45%5C%2C%5Cmathrm%7Bkg%7D%29%5Cleft%28200%5C%2C%5Cdfrac%7B%5Cmathrm%20m%7D%7B%5Cmathrm%20s%5E2%7D%5Cright%29)
![\implies F=90\,\dfrac{\mathrm{kg}\,\mathrm m}{\mathrm s^2}=90.\,\mathrm N](https://tex.z-dn.net/?f=%5Cimplies%20F%3D90%5C%2C%5Cdfrac%7B%5Cmathrm%7Bkg%7D%5C%2C%5Cmathrm%20m%7D%7B%5Cmathrm%20s%5E2%7D%3D90.%5C%2C%5Cmathrm%20N)
Answer:
0-4 acceleration comes at 12 m/s where (B) stagnates at 12 m/s and remains for 4 seconds (C) is breaks being activated slowing the car to 6 m/s in 2 seconds and (D) over the course of 4 seconds brings the car to 10 m/s.
Explanation: