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3 years ago

5

You are walking along a small country road one foggy morning and come to an intersection. while you are crossing, you hear an am

bulance siren. as a paramedic, you know that the siren sounds at a frequency of 5.87 khz. but, as an amateur musician with perfect pitch, you can tell that the frequency you are hearing is actually 5.29 khz. is the ambulance moving toward or away from you?

1 answer:

monitta3 years ago

6 0

You're hearing a higher frequency than the sound that's actually coming from the siren on the ambulance, so it must be moving TOWARD you.

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Steam enters a well-insulated nozzle at 200 lbf/in.2 , 500F, with a velocity of 200 ft/s and exits at 60 lbf/in.2 with a velocit

Ede4ka [16]

Answer:

$386.2^{\circ}F$

Explanation:

We are given that

$P_1=200lbf/in^2$

$P_2=60lbf/in^2$

$v_1=200ft/s$

$v_2=1700ft/s$

$T_1=500^{\circ}F$

$Q=0$

$C_p=1BTU/lb^{\circ}F$

We have to find the exit temperature.

By steady energy flow equation

$h_1+v^2_1+Q=h_2+v^2_2$

$C_pT_1+\frac{P^2_1}{25037}+Q=C_pT_2+\frac{P^2_2}{25037}$

$1BTU/lb=25037ft^2/s^2$

Substitute the values

$1\times 500+\frac{(200)^2}{25037}+0=1\times T_2+\frac{(1700)^2}{25037}$

$500+1.598=T_2+115.4$

$T_2=500+1.598-115.4$

$T_2=386.2^{\circ}F$

7 0

3 years ago

☆ Correct and rewrite the following statements:

kvv77 [185]

Answer:

<h3>e)</h3><h3><u>Question</u><u>:</u><u>-</u></h3>

Electroplating is based on magnetic effect of electricity.

<h3><u>Answer</u><u>:</u><u>-</u></h3>

<em>It's</em><em> </em><em>incorrect</em><em> </em><em>sentence</em><em> </em>
As we know that, while electroplating there are two rods, one becoming cathode and another one becoming anode. During electroplating, when electricity is given through the rods, the anode produces positive ions which gets received at the cathode rod and negative ions produced at cathode collects at anode rod which results to the plating of the desired substance. Here, it is a chemical effect of electricity resulting to plating.

<u>So correct sentence is:</u>

<em>Electroplating</em><em> </em><em>is</em><em> </em><em>based</em><em> </em><em>of</em><em> </em><em>chemical</em><em> </em><em>effect</em><em> </em><em>of</em><em> </em><em>electricity</em><em>.</em><em> </em>

<h3>f)</h3><h3><u>Question</u><u>:</u><u>-</u></h3>

An electric bulb glows due to the chemical effect of electricity.

<h3><u>Answer</u><u>:</u><u>-</u></h3>

<em>It's</em><em> </em><em>incorrect</em><em> </em><em>sentence</em><em> </em>
As we know that, in an electric bulb there is a filament. When electricity is given in that filament of the electric bulb, the filament gets intensely heated up and results to the emission of light. Due to this heating of the filament due to electricity the electric bulb glows.

<u>So correct sentence is:</u>

<em>A</em><em>n electric bulb glows due to the </em><em>h</em><em>e</em><em>a</em><em>t</em><em>i</em><em>n</em><em>g</em><em> </em><em>effect of electricity.</em>

6 0

2 years ago

The angle of reflection is the angle the ____ to the reflecting surface.

Arlecino [84]

Answer:

The angle of reflection is the angle the reflected rays make with a perpendicular line to the reflecting surface.

Explanation:

Reflection It is the change of direction suffered by a luminous ray when hitting the surface of an object. The angle of reflection is that which is formed by the reflected ray and the normal vector to the study surface

7 0

3 years ago

Please hellllooooppp

Lena [83]

Answer:

to the east i would say as i have tryed looking it up and carnt fimd the answer so i would saythe east or the north

Explanation:

you should choose as i dont no as it is a toss between those two

8 0

2 years ago

This procedure has been used to "weigh" astronauts in space: A 42.5 kg chair is attached to a spring and allowed to oscillate. W

Bingel [31]

Answer:

The mass of the astronaut is approximately 119.74 kg

Explanation:

Assuming this problem as a Simple Harmonic Motion of a mass-spring system, the period (T) of the oscillations for a mass (m) and spring constant (k) is:

$T=2\pi\sqrt{\frac{m}{k}}$ (1)

First, we have to calculate the spring constant using equation (1) and the data provided for the oscillations without the astronaut:

<em>(it’s important to note that one complete vibration is the period of the movement)</em>

$1.3=2\pi\sqrt{\frac{42.5}{k}}\Longrightarrow k=42.5(\frac{2\pi}{1.3})^{2}$

$k\approx992.8\,\frac{N}{m}$

Now with the value of k, we can use again (1) to find the mass of the astronaut (Ma) that makes the period to be 2.54 seconds

$2.54=2\pi\sqrt{\frac{42.5+M_{a}}{992.8}}\Longrightarrow M_{a}=992.8(\frac{2.54}{2\pi})^{2}-42.5$

$\mathbf{M_{a}\approx119.74\,kg}$

3 0

3 years ago