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mylen [45]
3 years ago
12

a man can row about 4kmperhr in a still water.he rows the boat 2km up the stream and 2km back to his starting point in 2hr.how f

ast is the stream flowing. ​
Physics
1 answer:
Nat2105 [25]3 years ago
7 0

<u>Answer</u>:

The stream flowing  at a speed of 2.828 \mathrm{km} / \mathrm{hr}

<u>Explanation</u>:

Given:  

Distance = 2km (both in upstream and downstream)  

The speed in still water be x km/hr.  

The speed in upstream = 4-x  

Speed in downstream = 4+x  

Solution:

We know that, Speed = distance/time  

So, Time = distance/speed

Therefore,  

2=\left(\frac{2}{4-x}\right)+\left(\frac{2}{4+x}\right)

2=\frac{2(4+x)+2(4-x)}{(4-x)(4+x)}

2(4-x)(4+x)=2(4+x)+2(4-x)

2(4-x)(4+x)=2(4+x+4-x)

By cancelling 2 on both sides,

16-x^{2}=8

x^{2}=16-8=8

x=\sqrt{8}

x=2.828 \mathrm{km} / \mathrm{hr}

Result:

Thus the speed of the stream is 2.828 \mathrm{km} / \mathrm{hr}

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Answer:

Explanation:

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Putting the values

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Similarly for 54 dB sound intensity can be given as follows

I = 10⁻¹² x 10^{5.4}

I= 10^{-6.6 } W / m²

For intensity of sound the relation is as follows

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Putting the given values for 71 dB

I= 10^{-4.9}  = 2π² x 504²xA²x 1.21 x  346

A² = 60.03 x 10⁻¹⁶

A = 7.74 x 10⁻⁸ m

For 54 dB sound

10^{-6.6} = 2π² x 504²xA²x 1.21 x  346

A² = 1.1978 x 10⁻¹⁶

A = 1.1 x 10⁻⁸ m

6 0
3 years ago
If the voltage across the first capacitor (the one with capacitance
RoseWind [281]
The answer to this question is: it depends. It depends on the arrangement of the capacitors in a circuit: it can be either in series or in parallel. The difference is shown in the picture. 

Capacitors are like batteries in a way that they store power from the source. It has some rules depending on the type of circuit. For parallel circuits, the voltage across each capacitor is equal. Therefore, V₁=V₂=V₃.

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The transfer of heat by the movement of a fluid is called: Think about it: Imagine a pocket of air over the land (“land air”), a
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Answer:

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Explanation:

Heat transfer by convection is the transfer of heat by fluid transport from one place to another, such that convection takes place when the heat that comes in contact of fluid containing body is moved to other parts of the container by the transporting fluid

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Convection heat transfer is a combination of conduction and advection heat transfer

7 0
2 years ago
If two bicycles of same masses move at different velocities,it will be easier to stop the bicycle that is moving at lower veloci
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Answer:

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When it comes to moving bicycles, the force that stops their movement is called "friction." Applying the law of motion, the higher the speed, the higher the force<em> </em>that is needed to stop it while the lower the speed, the lower the force<em> </em>that is needed to stop it.

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The kinetic energy decreases 
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