# Potential difference required to stop a particle

## Homework Statement

A particle with a charge-to-mass ratio of 50 C/kg is moving at a speed of 200 m/s. What electric potential difference is required to stop the particle?

F = Eq?

## The Attempt at a Solution

I am completely uncertain how to start this problem. Perhaps somebody can start me off?

$$\frac{1}{2}mv^2=qV$$