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3 years ago

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A boat is able to move through still water at 20m/s. It makes a round trip to.a town 3km upstream.If the river flows at 5m/s,the

times required for the round trip.is

1 answer:

marishachu [46]3 years ago

8 0

Answer:

the answer is 320 seconds :)

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The heart has structures that are called_____. This allows the blood to move in one direction.

Anarel [89]

Answer:

valves

The heart has four valves - one for each chamber of the heart. The valves keep blood moving through the heart in the right direction.

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3 years ago

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In the following diagrams the larger vector has a magnitude of 10, and the smaller

Anton [14]

the sum of vectors with the Pythagorean theorem allows us to find that the maximum magnitude occurs for the case:

d) the two vectors are parallel

Vectors are physical quantities that have modulus and direction, for example: force, velocity, acceleration, etc.

Vector algebra has defined the sum, the product by a scalar and by a vector. The modulus and the direction of the resulting vector must be encoded.

The sum of two quantities is done using the Pythagorean theorem

c² = a² + b²

where c is the resultant called hypotenuse, a and b are the summing vectors called legs; trigonometry is used for the direction.

Let's apply this expression to the present case

a, b) perpendicular vectors

c² = a² + b²

c = $\sqrt{6^2+10^2}$

c = 11.7

the magnitude is the same in both cases, changing the direction of the vector

c) Antiparallel vectors

For this case the vectors are collinear, so the sum reduces to the algebraic addition

c = a-b

c = 6 -10

c = -4

d) parallel vectors

c = a + b

c = 4 + 10

c = 14

We can see that the vectors addition gives their maximum and minimum values when the vectors are collinear.

In conclusion using the vectors addition we find that the correct answer is

d) the two vectors are parallel

learn more about vector addition here:

brainly.com/question/15074838

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3 years ago

Write short letters.

Svetradugi [14.3K]

Answer:

No. 67

Peter Street

12th Road

Chennai

24th June 201_

Dear Amrish

I have come to know that since your school has closed for the Autumn Break you have plenty of free time at your disposal at the moment. I would like to tell you that even I am having holidays now.

It has been a long time since we have spent some time together. If you are free, I would welcome to have your company this weekend. Why don’t you come over to my house and spend a day or so with me?

I am anxiously waiting for your reply.

Yours affectionately

your name

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3 years ago

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In order to be considered a vector, a quantity must include what two components? A. Magnitude

shepuryov [24]

In order to be considered a vector, a quantity must include Magnitude (A) and Direction (D).

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3 years ago

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A sphere of radius R contains charge Q spread uniformly throughout its volume. Find an expression for the electrostatic energy c

tensa zangetsu [6.8K]

Answer:

$E = \frac{3kQ^2}{5R}$

Explanation:

Let the sphere is uniformly charge to radius "r" and due to this charged sphere the electric potential on its surface is given as

$V = \frac{kq}{r}$

now we can say that

$q = \frac{Q}{\frac{4}{3}\pi R^3} (\frac{4}{3}\pi r^3)$

$q = \frac{Qr^3}{R^3}$

now electric potential is given as

$V = \frac{k\frac{Qr^3}{R^3}}{r}$

$V = \frac{kQr^2}{R^3}$

now work done to bring a small charge from infinite to the surface of this sphere is given as

$dW = V dq$

$dW = \frac{kQr^2}{R^3} dq$

here we know that

$dq = \frac{3Qr^2dr}{R^3}$

now the total energy of the sphere is given as

$E = \int dW$

$E = \int_0^R \frac{kQr^2}{R^3} (\frac{3Qr^2dr}{R^3})$

$E = \frac{3kQ^2}{R^6} (\frac{R^5}{5} - 0)$

$E = \frac{3kQ^2}{5R}$

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4 years ago