"A proton has an initial speed of 4.9×105 m/s . Part A What potential difference is required to bring the proton to rest? Express your answer using two significant figures."

Explanation:

The kinetic energy will be converted into electric potential energy, so we write:

We want the potential difference needed for this to happen, which is:

Where m and q are the mass and charge of the proton. We then use values:

an electric circuit