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4 years ago

5

Which of the following best describes magnetic fields? Question 4 options: Magnetic fields must have only positive charges. Magn

etic fields are always found in insulators. Magnetic fields need a conductor. Magnetic fields have north and south magnetic poles.

2 answers:

pochemuha4 years ago

8 0

<h3><u>Answer;</u></h3>

Magnetic fields have north and south magnetic poles.

<h3><u>Explanation;</u></h3>

<em><u>Magnetic fields are generated whenever charge is in motion. Magnets are those materials that have the capability to generate magnetic fields. </u></em>
<em><u>Magnetic fields have various characteristics which includes; they originate from the north poles and flow towards the south poles, they are exhibited in the form of magnetic field lines.</u></em> Magnetic fields lines never cross one another,they all have the same strength and seek the path of least resistance between opposite magnetic poles etc.

Kobotan [32]4 years ago

7 0

<span> Magnetic fields have north and south magnetic poles.</span>

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Given that an integer variable count has already been declared and assigned a value: Write a statement that writes the value of

Natalija [7]

Answer:

cout<<count;

Explanation:

cout<<count;

The above is a C++ command will write to the standard output device (stdout).

That means that one is printing an output on the main output device for that session... whatever that may be (any output device such as monitor, printer, the user's console, a tty session, a file etc).

What that device may be varies depending on how the program is being run and from where.

The kind of statement that writes to standard output are print statement

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3 years ago

Read 2 more answers

9. When a balloon rises into the air, it

Ksenya-84 [330]

Answer:

Answer 3: When a balloon goes up higher in the air, its size will increase. Since there's less air in the upper atmosphere, there's less stuff pushing back on the balloon, and hence the pressure is lower, which allows the balloon to expand

Answer: C

Explanation:

As the balloon rises, the gas inside the balloon expands because the atmospheric pressure surrounding the balloon drops. The atmosphere is 100 to 200 times less dense at the float altitudes than on the ground. and as the air is heated inside the balloon it causes it to rise upwards (because it is lighter than the cooler air on the outside). When the pilot needs to bring the balloon down again, he simply reduces the temperature of the air inside the balloon causing it to slowly descend.

4 0

2 years ago

Makovka662 [10]

Answer:

(A). The magnitude of the momentum of the marble is 0.004745 kg m/s.

(B). The speed of baseball is 23.0 m/s

Explanation:

Given that,

Mass of marble = 0.0073 kg

Speed = 0.65 m/s

(A). We need to calculate the magnitude of the momentum of the marble

Using formula of momentum

$p = mv$

Where, m = mass

v = velocity

Put the value into the formula

$p=0.0073\times0.65$

$p=0.004745\ kg m/s$

(B). Mass of baseball = 0.136 kg

Momentum of baseball = 3.14 kg m/s

We need to calculate the speed of baseball

Using formula of momentum

$p=mv$

$v=\dfrac{p}{m}$

Put the value into the formula

$v=\dfrac{3.14}{0.136}$

$v=23.0\ m/s$

Hence, (A). The magnitude of the momentum of the marble is 0.004745 kg m/s.

(B). The speed of baseball is 23.0 m/s

7 0

3 years ago

On a frozen pond, a 10.3 kg sled is given a kick that imparts to it an initial speed of vo = 1.64 m/s. The coefficient of kineti

alukav5142 [94]

Answer:

d=1.07m

Explanation:

Calculate Initial Kinetic Energy:

KE = 1/2*m*v^2

KE= 0.5*(10.3kg)*(1.64m/s)^2 = 13.85J

Calculate work overcoming friction:

W = F*d = mu*m*g*d

W = (0.128)*(10.3kg)*9.80m/s^2)*d

W = 12.92*d

Equate the two since all of the kinetic energy is used up in working against friction:

W = KE

12.92d = 13.851J

Solve for d:

d= (13.851J)/(12.92) = 1.07 m

5 0

4 years ago

A metal has a strength of 414 MPa at its elastic limit and the strain at that point is 0.002. Assume the test specimen is 12.8-m

ser-zykov [4K]

To solve this problem, we will start by defining each of the variables given and proceed to find the modulus of elasticity of the object. We will calculate the deformation per unit of elastic volume and finally we will calculate the net energy of the system. Let's start defining the variables

Yield Strength of the metal specimen

$S_{el} = 414Mpa$

Yield Strain of the Specimen

$\epsilon_{el} = 0.002$

Diameter of the test-specimen

$d_0 = 12.8mm$

Gage length of the Specimen

$L_0 = 50mm$

Modulus of elasticity

$E = \frac{S_{el}}{\epsilon_{el}}$

$E = \frac{414Mpa}{0.002}$

$E = 207Gpa$

Strain energy per unit volume at the elastic limit is

$U'_{el} = \frac{1}{2} S_{el} \cdot \epsilon_{el}$

$U'_{el} = \frac{1}{2} (414)(0.002)$

$U'_{el} = 414kN\cdot m/m^3$

Considering that the net strain energy of the sample is

$U_{el} = U_{el}' \cdot (\text{Volume of sample})$

$U_{el} = U_{el}'(\frac{\pi d_0^2}{4})(L_0)$

$U_{el} = (414)(\frac{\pi*0.0128^2}{4}) (50*10^{-3})$

$U_{el} = 2.663N\cdot m$

Therefore the net strain energy of the sample is $2.663N\codt m$

6 0

3 years ago