In alpha decay, an alpha particle (a helium nucleus consisting of two protons and two neutrons) escapes from a heavy nucleus and is propelled away by electrostatic forces. For example, a radon nucleus (atomic number 86) will spontaneously transform into a polonium nucleus (atomic number 84) and an alpha particle. Immediately after this transformation, both the polonium nucleus and the alpha particle can be assumed to be at rest and separated by approximately 50 x 10-15 m.

a. What is the initial electric potential energy of the alpha particle?

b. What is the velocity of the alpha particle when it is far from the polonium nucleus? Since the polonium nucleus is much more massive than the alpha particle, assume the polonium stays approximately at rest.

c. How far from the polonium nucleus is the alpha particle when it achieves 90% of the velocity calculated in (b)?