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3 years ago

What is one advantage of using electromagnets instead of permanent magnets

2 answers:

5 0

The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.

olganol [36]3 years ago

4 0

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Jake calculates that the frequency of a wave is 230 hertz, and its wave is moving at 460 m/s. What is the wavelength of the wave

Nesterboy [21]

Wavelength = (speed) / (frequency) = (460 m/s) / (230/sec) = <em>2 meters</em>

3 0

3 years ago

a person does 100 joules of work in pulling back the string of a bow. what will be the initial speed of a 0.5 kg arrow when it i

eduard

If all the energy she put into bending the bow is completely
transmitted to the arrow, then the arrow has the 100 joules
of kinetic energy when it leaves the bow.

   Kinetic energy = (1/2) (mass) (speed)²

   100 J = (1/2) (0.5 kg) (speed²)

Divide each side by 0.25 kg: 100 J / 0.25 kg = speed²

[ joule ] = [ newton-meter ] = kg-m²/sec²

100 kg-m²/sec² / 0.25 kg = speed²

   400 m²/sec² = speed²

Take the square root of each side: speed = √400 m/s

    20 m/s

      (about 44.7 mph)

3 0

3 years ago

If a pizza delivery guy declares himself the leader over the other pizza delivery people, he probably won't have many people obe

NemiM [27]

Answer:

the last one i think...

4 0

3 years ago

Explain why mess extinctions occur and why it make sense to measure geologic time between mass extinctions

Nastasia [14]

Mass extinction occur from natural disasters, such as a n asteroid hitting earth or a volcano errupting and spread ash everywhere.

It makes sense to measure geologic time between mass extinctions because after each mass extinction, there is almost no life left and the few left have to repopulate, which may lead way to new mutations and new varieties of plants and animals.
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3 0

3 years ago

A 14.0 gauge copper wire of diameter 1.628 mmcarries a current of 14.0 mA. Part A: What is the potential difference across a 2.1

FrozenT [24]

Answer:

for copper potential difference is 2.4871 × $10^{-4}$ V

for silver potential difference is 2.1256 × $10^{-4}$ V

Explanation:

given data

diameter D = 1.628 mm = 0.001628 m

current = 14.0 mA = 0.0140 A

length L = 2.15 m

to find out

potential difference

solution

we consider here

resistivity of silver = 1.47 × $10^{-8}$ ohm-m

resistivity of copper = 1.72 × $10^{-8}$ ohm-m

so we apply here resistance formula that is

Resistance = ρ × L / A ...............1

so here area A = πr² = π(0.001628 /2)² = 2.0816 × $10^{-6}$ m²

for copper Resistance = ρ × L / A

Resistance = 1.72 × $10^{-8}$ × 2.15 / 2.0816 × $10^{-6}$

Resistance = 1.7765 × $10^{-2}$ ohm

for silver Resistance = ρ × L / A

Resistance = 1.47 × $10^{-8}$ × 2.15 / 2.0816 × $10^{-6}$

Resistance = 1.5183 × $10^{-2}$ ohm

potential difference is calculated as

for copper potential difference = current × resistance

potential difference = 0.0140 ×1.7765 × $10^{-2}$

potential difference = 2.4871 × $10^{-4}$ V

for silver potential difference = current × resistance

potential difference = 0.0140 × 1.5183 × $10^{-2}$

potential difference = 2.1256 × $10^{-4}$ V

7 0

3 years ago