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3 years ago

Somebody please help me

Physics

2 answers:

Ilia_Sergeevich [38]3 years ago

5 0

The answer would be a and d

Ira Lisetskai [31]3 years ago

3 0

No the answer is b using a heater...

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What is the frequency of a sound wave having a velocity of 341 meters/second and a wavelength of 0.8 meters?

ololo11 [35]

Velocity=frequency/wavelength
frequency=velocity*wavelength
f=341*0.8
f=272.8 Hz

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4 years ago

1. Which of the following types of energy is

Sholpan [36]

Answer:

Potential energy is stored energy and the energy of position––gravitational energy. There are several forms of potential energy. Electrical Energy is the movement of electrical charges. Everything is made of tiny particles called atoms.

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2 years ago

Exercise can lower levels of estrogen in the blood.

vladimir1956 [14]

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3 years ago

A length of copper wire carries a current of 11 A, uniformly distributed through its cross section. Calculate the energy density

NISA [10]

Answer:

a) $0.983 \frac{J}{m^3}$

b) $u_E =7.329x10^-3 \frac{J}{m^3}$

Explanation:

The energy density is "the energy per unit volume, in the electric field. The energy stored between the plates of the capacitor equals the energy per unit volume stored in the electric field times the volume between the plates".

A magnetic field is a "vector field that describes the magnetic influence of electric charges in relative motion and magnetized materials".

Part a

For this case we can assume use the equation for the magnetic field in terms of the energy per unit of volume.

$B=\sqrt{2\mu_o u}$

Where μ0 represent the permeability constant, also known as the magnetic constant. If we solve for u we got:

$u=\frac{B^2}{2\mu_o}$

We also know that the magnetic field can be expressed in terms of the current and the radius of action R like this:

$B=\frac{\mu_o i}{2\pi R}$

Replacing this on the formula for u we have:

$u=\frac{1}{2\mu_o}(\frac{\mu_o i}{2\pi R})^2$

And simplyfing we got:

$u=\frac{\mu_o i^2}{8\pi^2 R^2}$

Replacing the values given we have:

$u=\frac{(4\pix10^{-7} \frac{H}{m} (11A)^2}{8\pi^2 (0.0014m)^2} =0.983 \frac{J}{m^3}$

Part b

The density current is given by this formula $J=i/A$ and the resistance by $R=\frac{\rho l}{A}$

If we use the equation for the energy density we have this:

$u_E =\frac{1}{2}\varepsilon_o E^2 =\frac{\varepsilon}{2}(\rho J)^2=\frac{\varepsilon}{2}(\frac{iR}{l})^2$

And replacing the values given we have:

$u_E =\frac{8.85x10^{-12}\frac{F}{m}}{2}(\frac{11A(3700\frac{\Omega}{m})}{l})^2 =7.329x10^-3 \frac{J}{m^3}$

4 0

4 years ago

Match the words with their definitions.

GREYUIT [131]

a crack across rock layers caused by moving plates
molten rock - fault (a fault is a rupture or scission in a block of rocks that allows both parts from the scission to slide over each other)

horizontal intrusion - sill (a sill is a mass of igneous rock that intruded horizontally and laterally through rock layers already existent)

vertical intrusion - d(y)ke (a d(y)ke is also a mass of igneous rock, but this time that intruded vertically across rock layers, many times through an already existing crack)

natural, upward movement of rock layers - uplift (uplift is a geological process in which a portion of the Earth's crust is elevated from its original position due to plate tectonics)

4 0

3 years ago

Read 2 more answers