Lorentz force and Newton's law

In summary, this problem involves determining the dielectric function of a gas of particles with number density n, charge q, and mass m in the presence of a steady magnetic field in the z direction. An electric field in the x direction is applied and the x and y components of Newton's law are written using the Lorentz force equation. A solution for the velocity is assumed in the form of v_x(t)=v_{x0}e^{-i \omega t} and v_y(t)=v_{y0}e^{-i \omega t}. The equations are then solved to find v_x0 and v_y0 in terms of E_x and the cyclotron frequency, \omega_c = qB/m.
  • #1
v_pino
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Homework Statement



This problem asks you to work out the dielectric function of a gas of particles with number density n, charge q, and mass m, with a steady magnetic field applied in the z direction.

Assume an electric field in the x direction,

[tex] E_x(t)=E_xe^{-i \omega t} [/tex]

is applied. Write down the x and y components of the Newton’s Law using the Lorentz force equation and no damping. Assume a solution for the velocity of the form,

[tex] v_x(t)=v_{x0}e^{-i \omega t} [/tex]

and

[tex] v_y(t)=v_{y0}e^{-i \omega t} [/tex]

Solve for v_x0 and v_y0 in terms of E_x and the cyclotron frequency,

[tex] \omega_c = qB/m [/tex]

Homework Equations



[tex] \mathbf{F}=q(\mathbf{E}+\mathbf{v}\times \mathbf{B}) [/tex]

[tex] \mathbf{F}=m \mathbf{a} [/tex]

The Attempt at a Solution



[tex] m \frac{d \mathbf{v}}{dt}=q(\mathbf{E}+\mathbf{v}\times \mathbf{B}) [/tex]

[tex] \frac{dv_x}{dt}=-i \omega v_{x0}e^{-i \omega t} [/tex]

[tex] \frac{dv_y}{dt}=-i \omega v_{y0}e^{-i \omega t} [/tex]

I am having trouble pulling all these equations to write out the components of Newton's law.
 
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  • #2
I am not sure how to solve for v_x0 and v_y0 in terms of E_x and the cyclotron frequency. Any help would be greatly appreciated!
 

FAQ: Lorentz force and Newton's law

What is the Lorentz force?

The Lorentz force is the force exerted on a charged particle when it moves through an electric and magnetic field.

What is Newton's law of motion?

Newton's law of motion states that an object at rest will remain at rest, and an object in motion will continue in motion with the same velocity and in the same direction, unless acted upon by an external force.

How are the Lorentz force and Newton's law related?

The Lorentz force is a result of Newton's law of motion. It explains the relationship between the motion of a charged particle and the electric and magnetic fields it experiences.

What is the formula for the Lorentz force?

The formula for the Lorentz force is F = q(E + v x B), where F is the force, q is the charge of the particle, E is the electric field, v is the velocity of the particle, and B is the magnetic field.

What are some real-world applications of the Lorentz force and Newton's law?

The Lorentz force and Newton's law have many practical applications, such as in particle accelerators, electric motors, and generators. They also play a crucial role in understanding the behavior of charged particles in space, such as in the Earth's magnetic field and in the solar wind.

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