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Oduvanchick [21]

3 years ago

14

Write a hypothesis about the effect of the magnet polarity on the induced current. Use the "if . . . then . . . because . . ." f

ormat and be sure to answer the lesson question: "How does magnetic polarity affect the current flowing in a loop of wire?"

2 answers:

klemol [59]3 years ago

7 0

Explanation :

The induced current also depends on the polarity of the magnet. Mathematically, it is given as :

$E=-B\dfrac{d\phi}{dt}$

E is the induced emf, E = IR

B is the magnetic field

$\dfrac{d\phi}{dt}$ is the rate of change of magnetic flux.

$I=-\dfrac{B}{R}\dfrac{d\phi}{dt}$

I is the induced current.

The direction of electromagnetic force is determined by polarity of the magnet.

If the polarity of the magnet is reversed then the induced current will also reversed because the direction of electromagnetic force depends on the polarity of the magnet.

Simora [160]3 years ago

3 0

<span>If the polarity of a moving magnet is reversed, then the current induced in a loop of wire will reverse in direction, because magnet polarity determines the direction of the electromagnetic force.</span>

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Amanda [17]

Answer:

The illumination on the book before the lamp is moved is 9 times the illumination after the lamp is moved.

Explanation:

The distance of the book before the lamp is moved, $d_{b} = 30 cm$

The distance of the book after the lamp is moved, $d_{a} = 90 cm$

Illumination can be given by the formula, $E = \frac{P}{4 \pi d^{2} }$

Illumination before the lamp is moved, $E_{b} = \frac{P}{4 \pi d_{b} ^{2} }$

Illumination after the lamp is moved, $E_{a} = \frac{P}{4 \pi d_{a} ^{2} }$

$\frac{E_{a}}{E_{b}} } = \frac{\frac{P}{4 \pi d_{a} ^{2} } }{\frac{P}{4 \pi d_{b} ^{2} } }$

$\frac{E_{a} }{E_{b} } = \frac{d_{b} ^{2} }{d_{a} ^{2}} \\\frac{E_{a} }{E_{b} } = \frac{30^{2} }{90 ^{2}}\\\frac{E_{a} }{E_{b} } =\frac{900 }{8100}\\\frac{E_{a} }{E_{b} } =\frac{1 }{9}$

$E_{b} = 9E_{a}$

The illumination on the book before the lamp is moved is 9 times the illumination after the lamp is moved.

6 0

3 years ago

A 20" round duct is 275' in length. The duct is carrying 2,900 CFM at a friction loss of 0.12 inches WG per 100 feet.

ivolga24 [154]

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2 years ago

An ice cube at 0c was dropped into 30.0 g of water in a cup at 45.0c. at the instant that all of the ice was melted, the tempera

Ede4ka [16]

The amount of heat given by the water to the block of ice can be calculated by using
$Q=m_w C_{sw} \Delta T_w$
where
$m_w = 30 g$ is the mass of the water
$C_{sw}=4.18 J/(g ^{\circ}C)$ is the specific heat capacity of water
$\Delta T_w = 45.0^{\circ}-19.5^{\circ}C = 20.5^{\circ}C$ is the variation of temperature of the water.

Using these numbers, we find
$Q=(30 g)(4.18 J/(g^{\circ}C))(20.5^{\circ}C)=2571 J$

This is the amount of heat released by the water, but this is exactly equal to the amount of heat absorbed by the ice, used to melt it into water according to the formula:
$Q = m_i L_f$
where $m_i$ is the mass of the ice while $L_f =334 J/g$ is the specific latent heat of fusion of the ice.
Re-arranging this formula and using the heat Q that we found previously, we can calculate the mass of the ice:
$m_i = \frac{Q}{L_f}= \frac{2571 J}{334 J/g} =7.7 g$

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2 years ago

Carmen is helping load furniture and boxes onto a moving truck. She picks up boxes of her things, places them on a cart, and pus

AleksandrR [38]

Answer:

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6 0

3 years ago

Read 2 more answers

A spring scale exerts a net force of 8.5 N on an object. What is the object's mass if it has an acceleration of

Amiraneli [1.4K]

Answer:

mass of the object is 2.18 kg

Explanation:

Given

Force (F) = 8.5 N = 8.5 kg.m/ $s^{2}$

acceleration (a) = 3.9 m/ $s^{2}$

Mass (m) = ?

We know that the newton's second law of motion gives the relation between mass of ab object. force acted upon and the amount the object is accelerated. It is expressed in the form of an equation:

F = ma

mass, m = F/a

= $\frac{8.5 kgms^{-2} }{3.9 ms^{-2} }$

= 2.18 kg

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3 years ago