Serway & Jewett — The Laws of Motion: Problem 11

Review. An electron of mass \(9.11 \times 10^{-31} \text{ kg}\) has an initial speed of \(3.00 \times 10^5 \text{ m/s}\). It travels in a straight line, and its speed increases to \(7.00 \times 10^5 \text{ m/s}\) in a distance of \(5.00 \text{ cm}\). Assuming its acceleration is constant, (a) determine the magnitude of the force exerted on the electron and (b) compare this force with the weight of the electron, which we ignored.