1. The problem statement, all variables and given/known data One of the three types of radioactive decay is "β decay", during which protons decay into neutrons or viceversa, emitting either electrons (β) or positrons (β+) at high velocity as a result. In one experiment, a β source and β+ source are placed 10 cm apart from each other. At a certain time, both sources decay simultaneously, with the electron being emitted along the xaxis and the positron being emitted along the yaxis (i.e. the paths of the two particles are at a right angle). Both particles are emitted with 5 keV(kiloelectron volts) of kinetic energy and start on the xaxis. What is magnitude and direction of the total force on each particle? (Do not ignore electric force, assume electrons and positrons have the same mass.) 2. Relevant equations ΔE=Ui+Uf=−∫F.dr=>F=−∇E 3. The attempt at a solution I attempted to solve this using conservation of energy. Initially, we have both kinetic and potential energy. Kinetic energy is given to us and we can find electric potential energy. I'm assuming the total final energy (kinetic + potential) is zero since Vf = 0 and Uf = 0 (since distance between the two particles gets "infinitely" long). I then tried to use the equation ΔE=Ui+Uf=−∫F.dr=>F=−∇E But I'm not sure how this would help. I feel like I'm missing something. The fact that the question states "don't ignore electric force" makes me think I have to use it, but then if I'm using the electric force formula what's the point of having the initial energy? Any help would be appreciated.