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2 years ago

If you are sitting 8.20 m from a

Physics

1 answer:

Elanso [62]2 years ago

8 0

Answer:

Explanation:

There are a lot of assumptions needed for the calculation:

first is the speaker is a point source

second the speaker is 100% efficient in its output

third the sound output propagates as a sphere

Intensity = Power / Surface Area

= 70 / (4*pi*8.20^2)

= 0.082W/m^2

Converting into dB:

= 10*log ( Intensity / (1*10^-12))

= 10*log(0.0828/ (1*10^-12))

= 109 dB

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a race car accelerates uniformly from 18.5 m/s to 46.1m/s in 2.47 seconds detrrmine the acceleration of the car and distance tra

LenaWriter [7]

Because acceleration is constant, the acceleration of the car at any time is the same as its average acceleration over the duration. So

$a=\dfrac{\Delta v}{\Delta t}=\dfrac{46.1\,\frac{\mathrm m}{\mathrm s}-18.5\,\frac{\mathrm m}{\mathrm s}}{2.47\,\mathrm s}=11.2\,\dfrac{\mathrm m}{\mathrm s^2}$

Now, we have that

${v_f}^2-{v_0}^2=2a\Delta x$

so we end up with a distance traveled of

$\left(46.1\,\dfrac{\mathrm m}{\mathrm s}\right)^2-\left(18.5\,\dfrac{\mathrm m}{\mathrm s}\right)^2=2\left(11.2\,\dfrac{\mathrm m}{\mathrm s^2}\right)\Delta x$

$\implies\Delta x=79.6\,\mathrm m$

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3 years ago

Which of the following statements are TRUE about nuclear energy?

san4es73 [151]

Answer:

Explanation:

4 0

2 years ago

If 36 grams of water is to be heated from 24.0°C to 48°C to make a cup of tea, how much heat must be added? The specific heat of

Vinvika [58]

We will have the following:

$\begin{gathered} Q=mc\Delta T\Rightarrow Q=(36)(4.18)(48-24) \\ \\ \Rightarrow Q=3611.52 \end{gathered}$

So, the heat to add is 3611.52 Joules.

3 0

10 months ago

Two trains are traveling side-by-side along parallel, straight tracks at the same speed. In a time t, train A doubles its speed.

sergij07 [2.7K]

Answer:

derdddrdickdd

Explanation:

3 0

2 years ago

The mass of a radioactive substance follows a continuous exponential decay model, with a decay rate parameter of 1% per day. A s

Bumek [7]

Answer:

2,38kg

Explanation:

Mass in function of time can be found by the formula: $m_{(t)} =m_{0} e^{-kt}$ , where $m_{0}$ is the initial mass, t is the time and k is a constant.

Given that a sample decay 1% per day, that means that after first day you have 99% of mass.

$m_{(1)} =m_{0} e^{-k(1)}$ , but $m_{(1)}=\frac{99m_{0} }{100}$ , so we have $\frac{99m_{0} }{100}=m_{0}e^{-k}$ , then $k=-ln(\frac{99}{100})=0.01$

Now using k found we must to find $m_{(5)}$ .

$m_{(5)}=m_{0}e^{-(0.01)5}=2.5kge^{-0.05} =2.5x0.951=2.38kg$

6 0

2 years ago