A proton has an initial speed of 40times105ms what

Question

Solve the all parts of given question:

Question: A proton has an initial speed of 4.0×10⁵m/s,

Part I: What potential difference is required to bring the proton to rest?

Part II: What potential difference is required to reduce the initial speed of the proton by a factor of 2?

Part III: What potential difference is required to reduce the initial kinetic energy of the proton by a factor of 2?

Please show all work and express your answer using two significant figures. Thanks.