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3 years ago

What inductance l would be needed to store energy e=3.0kwh (kilowatt-hours) in a coil carrying current i=300a?

1 answer:

5 0

The formula for the energy stored in the magnetic field of an inductor is:

E = (1/2) (inductance) (current)² .

In the present situation:

Energy = (3 kilo-watt-hour) x (1,000 / kilo) x (joule/watt-sec) x (3,600 sec/hr)

   = (3 · 1000 · 3,600) (kilo·watt·hr·joule·sec / kilo·watt·sec·hr)

   =    1.08 x 10⁷ joules .

Now to find the inductance:

   E = (1/2) (inductance) (current)²

   (1.08 x 10⁷ joules) = (1/2) (inductance) (300 Amp)²

   (2.16 x10⁷ joules) = (inductance) (300 Amp)²

   Inductance = (2.16 x10⁷ joules) / (300 Amp)²

=   2.16 x10⁷ / 90,000    Henrys

   I get    240 Henrys .

This is a big inductance. Possibly the size of your house.
To get a big inductance, you want to wind the coil
with a huge number of turns of very fine wire, in
a small space.
In this case, however, if you plan on running 300A through
your coil, it'll have to be wound with a very thick conductor ...
like maybe 1/4-inch solid copper wire, or even copper tubing,
You have competing requirements.
There are cheaper, easier, better ways to store 3 kWh of energy.
In fact, a quick back-of-the-napkin calculation says that
3 or 4 car batteries will do the job nicely.

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The density of lead is 11.3 g/cm3. what mass of lead is required to make a 1.00 cm3 fishing sinker?

Elza [17]

The mass of lead required to make a 1.00 cm3 fishing sinker is 11.3g.

What is mass?

Mass is a metric used in physics to express inertia, a fundamental characteristic of all matter. A mass of matter's resistance to altering its direction or speed in response to the application of a force is what it essentially is. The change that an applied force produces is smaller the more mass a body has.

Given :

Density of lead = 11.3 g/cm3

Volume of sinker = 1.00 cm3

One of a substance's attributes is density, which is calculated by dividing the mass by the volume. Mathematically:

Density : Mass / volume

therefore after putting the values,

mass= 11.3g

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1 year ago

Which of the following statements is accurate? A. Sound waves passing through the air will do so as transverse waves, which vibr

egoroff_w [7]

The answer is, C. the wavelength is measured in parallel to the direction of the wave, at any point, under the same repetition for any type of wave.

7 0

3 years ago

Read 2 more answers

A charge of -8.5 µC is traveling at a speed of 9.0 106 m/s in a region of space where there is a magnetic field. The angle betwe

Sindrei [870]

Answer:

The magnitude of the magnetic field is $9.3\times 10^{-5}\ T$ .

Explanation:

Given that,

Charge, $q=-8.5\ \mu C=-8.5\times 10^{-6}\ C$

Speed of the charged particle, $v=9\times 10^6\ m/s$

The angle between the velocity of the charge and the field is 56°.

The magnitude of force, $F=5.9\times 10^{-3}\ N$

We need to find the magnitude of the magnetic field. When a charged particle moves in the magnetic field, the magnetic force is experienced by it. The force is given by :

$F=qvB\ \sin\theta$

B is the magnetic field.

$B=\dfrac{F}{qv\ \sin\theta}\\\\B=\dfrac{5.9\times 10^{-3}}{8.5\times 10^{-6}\times 9\times 10^6\ \sin(56)}\\\\B=9.3\times 10^{-5}\ T$

So, the magnitude of the magnetic field is $9.3\times 10^{-5}\ T$ . Hence, this is the required solution.

4 0

3 years ago

How would a spinning disk's kinetic energy change if its moment of inertia was five times larger but its angular speed was five

Keith_Richards [23]

Answer:

The kinetic energy of a spinning disk will be reduced to a tenth of its initial kinetic energy if its moment of inertia is made five times larger, but its angular speed is made five times smaller.

Explanation:

Let us first consider the initial characteristics of the angular motion of the disk

moment of inertia = $I$

angular speed = ω

For the second case, we consider the characteristics to now be

moment of inertia = $5I$ (five times larger)

angular speed = ω/5 (five times smaller)

Recall that the kinetic energy of a spinning body is given as

$KE = \frac{1}{2}Iw^{2}$

therefore,

for the first case, the K.E. is given as

$KE = \frac{1}{2}Iw^{2}$

and for the second case, the K.E. is given as

$KE = \frac{1}{2}(5I)(\frac{w}{5} )^{2} = \frac{5}{50}Iw^{2}$

$KE = \frac{1}{10}Iw^{2}$

this is one-tenth the kinetic energy before its spinning characteristics were changed.

This implies that the kinetic energy of the spinning disk will be reduced to a tenth of its initial kinetic energy if its moment of inertia is made five times larger, but its angular speed is made five times smaller.

6 0

3 years ago

The diagram shows a position-time graph What is the displacement of the object

algol13

The object is moving, so at different times, it has different displacement. I'm guessing that you probably want to know the displacement at the end of the time on the graph ... 5 seconds.

Displacement is the distance and the direction FROM (the position at the beginning) TO (the position at the end).

At the beginning ... time=0 ... the position is 1 meter.

At the end ... time=5 ... the position is zero.

The distance FROM the beginning TO the end is (zero - 1m) . That's -1m .

5 0

3 years ago