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3 years ago

1.What is an electromagnet ?

1 answer:

4 0

An electromagnet is a soft metal core made into a magnet by the passage of electric current through a coil surrounding it

The difference between a permanent magnet and an electro magnet is that a permanent magnet is made from a "hard" magnetic material that maintains its magnetism over long periods of time. The magnetism in an electromagnet is created by current running through a coil of insulated wire that is wound around a piece of "soft"magnetic material.

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Io experiences tidal heating primarily because __________. hints io experiences tidal heating primarily because __________. io i

maxonik [38]

Lo experiences tidal heating primarily because lo’s elliptical orbit causes the tidal force on lo to vary as it orbits the Jupiter. Thus, lo’s elliptical orbit is essential to its tidal heating. This elliptical orbit, in turn, is an end result of the orbital resonance among lo, Europa and ganymade. This orbital resonance origin lo to have a more elliptical orbit than it would because lo intermittently passes Europa and ganymade in the same orbital position. We cannot perceive tidal forces of tidal heating in lo but rather we foresee that they must occur based on the orbital characteristic of the moons and active volcanoes on lo is the observational evidence that tidal heating is significant in lo.

8 0

3 years ago

Suppose that the current in the solenoid is i(t). The self-inductance L is related to the self-induced EMF E(t) by the equation

Artemon [7]

Answer:

L = μ₀ n r / 2I

Explanation:

This exercise we must relate several equations, let's start writing the voltage in a coil

$E_{L}$ = - L dI / dt

Let's use Faraday's law

E = - d Ф_B / dt

in the case of the coil this voltage is the same, so we can equal the two relationships

- d Ф_B / dt = - L dI / dt

The magnetic flux is the sum of the flux in each turn, if there are n turns in the coil

n d Ф_B = L dI

we can remove the differentials

n Ф_B = L I

magnetic flux is defined by

Ф_B = B . A

in this case the direction of the magnetic field is along the coil and the normal direction to the area as well, therefore the scalar product is reduced to the algebraic product

n B A = L I

the loop area is

A = π R²

we substitute

n B π R² = L I (1)

To find the magnetic field in the coil let's use Ampere's law

∫ B. ds = μ₀ I

where B is the magnetic field and s is the current circulation, in the coil the current circulates along the length of the coil

s = 2π R

we solve

B 2ππ R = μ₀ I

B = μ₀ I / 2πR

we substitute in

n ( μ₀ I / 2πR) π R² = L I

n μ₀ R / 2 = L I

L = μ₀ n r / 2I

4 0

3 years ago

Approximate the human form as an unclothed vertical cylinder of 0.3 m diameter and 1.75 m length with a surface temperature of 3

Zolol [24]

Answer:

$q=1118.865W$

Explanation:

From the question we are told that

Diameter of the cylinder $D=0.3m$

Length of the cylinder $L=1.75m$

Surface temperature of cylinder $T_s=30 \textdegree C=303k$

Speed of air $V=10m/s$

Temperature of air $T=20 \textdegree C$

Generally the equation for Reynolds number is mathematically given by

$Re_D=\frac{VD}{v}$

where

$v=15.27*10^-^6$

$Re_D=\frac{10*0.3}{15.27*10^-^6}$

$Re_D=1.96*10^5$

Generally the equation for Nusselt number is mathematically given by

$N_u=0.6(Re_D)^{0.6}(Pr)^{0.37}$

where

Prandtl number

$Pr=0.71$

$N_u=0.6(Re_D)^{0.6}(Pr)^{0.37}$

$N_u=0.6(1.96*10^5)^{0.6}(0.71)^{0.37}$

$N_u=791.53$

Generally the equation for convective heat transfer is mathematically given by

$h=Nu \frac{k}{D}$

where

$k=25.7*10^{-3}$

$h=791.53*\frac{25.7*10^{-3}}{0.3}$

$h=67.81W/m^2K$

Generally the equation for surface area of a cylinder is mathematically given by

$A=\pi DL$

$A=\pi *0.3*1.75$

$A=1.65m^2$

Generally the equation for convective heat transfer is mathematically given by

$q=h4(T_s-T_{inty)}$

$q=(67.81)*1.65*(30-20)\\$

$q=1118.865W$

3 0

2 years ago

3a and c someone please help I really don't understand

earnstyle [38]

F_x=Fcos(a)
F_y=Fsin(a)

1.F_x=166cos(55)
F_y=166sin(55) (55 because of the supplementary angle)

2.F_x= 575cos(-75) (complimentary angle/negative because its under x-axis)
F_y= 575sin(-75)

The values you get can be negative or positive depending on which side the vector is pointing at.

3 0

3 years ago

The movement of thermal energy from a warmer object to a cooler object is called a. heat. b. temperature. c. motion. d. momentum

Ann [662]

Answer:

heat

Explanation:

because heat the other of transferring energy

4 0

3 years ago