Question

an electron of mass 9.11*10^-31 kg has an initial speed of 4.00*10^5 m/s. it travels in a straight line and its speed increases 8.00*10^5 m/s in a distance of 5.40 cm assume acceleration is constant

determine magnitued of the force exerted on the electron

Answer 1

vf^2=vi^2 + 2 a d
solve for a.

Then, yep, force=mass*acceleration