1. The problem statement, all variables and given/known data I am about to start AS Level Physics and have been given some questions/problems to solve as introductory homework. However, I am stuck on one and cannot seem to get the answer specified as the correct one. An electron of mass 9.11x10-31kg is accelerated by a positive charge such that the electron experiences a constant force of 8.5x10-29N. The electron, which was already moving, then travels 45mm in 35microseconds. By first determining the acceleration of the electron, calculate its initial velocity. 2. Relevant equations F = ma s = ut + 1/2at2 F = Force (N) m = mass (kg) a = acceleration (ms-2) s = distance travelled (m) u = initial velocity (ms-1) t = time (s) 3. The attempt at a solution Converting Units 45mm = 0.045m 35microseconds = 0.000035s Working Out Acceleration F =ma 8.5x10-29 = 9.11x10-31 x a 8.5x10-29 / 9.11x10-31 = a a = 93 + 277/911 Check: 9.11x10-31 x (93 + 277/911) = 8.5x10-29 ✓ Working Out Initial Velocity Rearranging the Equation: s = ut + 1/2at2 ut = s - 1/2at2 u = (s-1/2at2) / t Putting in the Values u = (0.045 - 1/2(93+277/911) x 0.0000352) / 0.000035 u = (0.045 - (1.142974755x10-7 x 1/2)) / 0.000035 u = (0.045 - 5.714873765x10-8) / 0.000035 u = 0.04499994285 / 0.000035 u = 1285.712653 According to the booklet, the answer should be 4290ms-1 and not the value I got. I have been working at this for hours and cannot seem to find where I am going wrong. Help me out?