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qwelly [4]
4 years ago
10

The attracting and repelling forces of magnets are used in countless objects, from refrigerator doors to maglev trains. Refriger

ator doors use the attraction of magnets to stay closed, while maglev trains use magnetic repulsion to hover above rails. The center magnet in the picture is hovering between two magnets, making it appear to float. Which best explains how the center magnet is able to hover between two other magnets?
A) The opposite poles of each magnet are facing each other, so they repel.
B) The magnets are stacked so that similar poles are facing one another.
C) The middle magnet is repelling the top magnet while attracting the bottom.
D) The middle magnet is attracted to the top magnet, but held down by gravity.
Physics
1 answer:
wariber [46]4 years ago
4 0

Answer: It's A

Explanation:

I took the test

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A train A travelled a distance of 150 km in 3 hours, whereas, train 'B"
ozzi

Answer:

Therefore, Train A is faster with 50km/h and a 5km/h difference

Explanation:

train A

150km/3h = 50km/h

train B

180km/4h = 45km/h

8 0
3 years ago
A thin, uniformly charged insulating rod has a linear charge density λ = 3 nC/m and lies along the x axis from x = 1m to x = 3m.
Contact [7]

Answer:

A) V_A = 11.93~V

B) The vector definition of E-field is

\vec{E} = -1.13\^x + 2.41\^y

where magnitude is E = 2.66 N/m.

Explanation:

The potential of a uniformly charged rod can be found by the method of integration. We will first choose an infinitesimal part on the rod. We will compute the potential of this part at point A. Then we will integrate this potential over the entire rod.

We will use the following formula for electric potential:

V = \frac{1}{4\pi \epsilon_0}\frac{Q}{r}

Let us choose the infinitesimal part a distance 'x' from the origin. Then the distance between this point and point A is

r = \sqrt{x^2+4^2}

The infinitesimal length is 'dx', and the potential of this length is dV. Let's apply the formula:

dV = \frac{1}{4\pi\epsilon_0}\frac{\lambda dx}{\sqrt{x^2 + 4^2}}

Here, the charge Q is equal to the charge density multiplied by the length. Q = λdx

Now we have to integrate this infinitesimal potential over the rod:

V = \int\limits^3_1 {dV} \, dx = \frac{1}{4\pi \epsilon_0}\int\limits^3_1 {\frac{\lambda}{\sqrt{x^2 + 16}} \, dx

By using an integral table, this can be calculated:

V = \frac{3\times 10^{-9}}{4\pi\epsilon_0}\ln(|\sqrt{x^2+16}+x|)\left \{ {{x=3} \atop {x=1}} \right. \\V = 11.93~V

B) The electric field can be found by a similar approach, but a different formula:

\vec{E} = \frac{1}{4\pi \epsilon_0}\frac{Q}{r^2}\^r

Let's apply this formula to the infinitesimal part we have chosen.

dE_x = \frac{1}{4\pi\epsilon_0}\frac{\lambda dx}{x^2 + 4^2}\cos(\theta)\\dE_y = \frac{1}{4\pi\epsilon_0}\frac{\lambda dx}{x^2 + 4^2}\sin(\theta)

By the geometry sine and cosine terms can be found:

\sin(\theta) = \frac{4}{\sqrt{x^2+16}}\\\cos(\theta) = \frac{x}{\sqrt{x^2 + 16}}

The x- and y-components of the E-field can be found separately by integrating the infinitesimal parts over the entire rod.

E_x = \int\limits^3_1 {dE_x} \, dx = \frac{\lambda}{4\pi\epsilon_0}\int\limits^3_1 {\frac{x}{(x^2+16)^{3/2}}} \, dx  = 1.13(-\^x)\\E_y = \int\limits^3_1 {dE_y} \, dx = \frac{4\lambda}{4\pi\epsilon_0}\int\limits^3_1 {\frac{1}{(x^2+16)^{3/2}}} \, dx  = 2.41(\^y)

So, the final E-field is

\vec{E} = -1.13\^x + 2.41\^y

The magnitude of the E-field is

E = 2.66 N/m

6 0
3 years ago
A circuit with resistive elements of 220, 100, 57, and 43 produce what total resistance?
Korvikt [17]

The total resistance is 420 ohm.

A circuit with resistive elements of 220, 100, 57, and 43 produce what total resistance  

 R= 220+ 100+ 57+ 43

    = 420 Ω

What is resistance and its types?

Resistance is a measure of the opposition to current flow in an electrical circuit also known as ohmic resistance or electrical resistance. Ohms are measured as resistance, symbolized by the Greek letter omega (Ω). The ratio of the applied voltage to the current through the material is then known as resistance.

What causes resistance?

An electric current flows when electrons move through a conductor, such as a metal wire. The moving electrons can collide with the ions in the metal. This makes it more difficult for the current to flow, and causes resistance.

Learn more about resistance:

brainly.com/question/17563681

#SPJ4

8 0
2 years ago
these are the sierra nevada mountains.ice wedging is one of the ways these mountains where weathered.please help
kramer

Answer:

D

Explanation:

7 0
3 years ago
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A push or a pull is called _____. User: The metric unit of force is the _____.
Ahat [919]
Force
Newton, abbreviated as N
7 0
3 years ago
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