Point A is at $-25\mathrm{V}$ and point B is at $400\mathrm{V}$. A proton moves past point A at $3.5\times {10}^5\mathrm{m}/\mathrm{s}$, what is its speed when it reaches point B?

• A. $2.8\times {10}^4\mathrm{m}/\mathrm{s}$
• B. $5.7\times {10}^4\mathrm{m}/\mathrm{s}$
• C. $1.0\times {10}^5\mathrm{m}/\mathrm{s}$
• D. $2.8\times {10}^5\mathrm{m}/\mathrm{s}$
• E. $1.9\times {10}^5\mathrm{m}/\mathrm{s}$