Shooting Particles - Part 2

Do as a GOAL Problem

A 2 mm-diameter plastic bead is charged to -1 nC.

1. An alpha particle (the nucleus of a helium atom with 2 protons, 2 neutrons, and no electrons) is fired at the bead from far away with a speed of 1e6 m/s and it collides head on with the bead. What is the impact speed?
   
   
2. An electron is fired at the bead from far away. It "reflects," with a turning point 0.1 mm from the surface of the bead. What was the electron's initial speed?