### The Rail Gun

Powered by electricity, rail guns are electromagnetic projectile launchers that are able to fire several pound projectiles at hypersonic speeds.

#### Amazing But True

- A rail gun is an apparatus that consists of two parallel guide rails that are connected to a power supply. When a conductive projectile is placed on the rails a magnetic field is created that is perpendicular to the rails. As a result, a Lorentz force is created that accelerates the projectile at a rate that is proportional to the current squared.
- The Lorentz force states that a charged particle that moves in the presence of an electric or magnetic field will experience a force of the form:

\begin{align*}F = q(\overrightarrow{E} + v \times \overrightarrow{B})\end{align*}

where \begin{align*}q\end{align*}

#### Explore More

Using the information provided above, and the link below, answer the following questions.

- If a charged particle has a velocity along the \begin{align*}x\end{align*}
x -axis, what direction would the Lorentz force be if the particle enters a region with an electric field pointed along the \begin{align*}y\end{align*}y -axis? - If a particle with zero charge has a velocity along the \begin{align*}x\end{align*}
x -axis, what direction would the Lorentz force be if the particle enters a region with a magnetic field pointed along the \begin{align*}y\end{align*}y -axis? - If the particle in the previous problem has a positive charge, what direction would the Lorentz force be?