Dealing with magnetic force into the page?

[jisbon]

Homework Statement

A charged particle beam is accelerated through a potential difference of
211 V, shot horizontally into a region where there is a constant magnetic
field of magnitude $2.45*10^{3}$ T that points straight down. The charged
particles then move in a circular path of radius 2.00 cm. Determine the
charge to mass ratio of the charged particles.

Relevant Equations

-

Since the magnetic field is pointing down, I can derive that the magnetic force is into the page. With this, I can't really imagine how the particle can move in a circular motion as I cannot visualise how the centripetal force will look like when the force is into the page (instead of usual problems where the field is into the page and the charge simply deflect up/downwards).

Any visualization/guidance will be appreciated. Thanks

 

[TSny]

The circular motion of a charged particle in a uniform B field is a standard topic. For example, you can read this short discussion and then ask questions here about anything that is not clear.

 

[jisbon]

The circular motion of a charged particle in a uniform B field is a standard topic. For example, you can read this short discussion and then ask questions here about anything that is not clear.

In this case here, I can assume that the particle is moving in a helical motion since the velocity is not perpendicular to the magnetic field (it is pointing downwards instead of in the page).
In this case, can I still use:

?
If so, I can also determine that:

Hence, I will have:

$\begin{aligned}\dfrac {1}{2}mv^{2}=211q\\ 0.02=\dfrac {mv}{2.45\times 10^{-3}\left( q\right) }\end{aligned}$$\begin{aligned}\dfrac {q}{m}=\dfrac {1}{422}v^{2}\\ \dfrac {q}{m}=\dfrac {v}{4.9\times 10^{-5}}\end{aligned}$
Will this be the correct approach?