1. The problem statement, all variables and given/known data An X-ray tube gives electrons constant acceleration over a distance of 20cm . If their final speed is 2.0×107m/s , what are the electrons' acceleration? 2. Relevant equations v final ^ 2 = v initial ^ 2 + 2a(x-x initial) 3. The attempt at a solution x = .2 m (after conversion from cm) v final is given. how do I find v initial? I need that so I can find acceleration.