An electron travelling at a speed of 2.6 x 108 m/s bas a mass of 18 x 10^-31 kg which is about twice the rest mass of an electron 9.1 x 10^-31 kg.
How large an average force is needed to accelerate the electron to this speed
from an initial speed of 1.0 x 108 m/s in a time of 1.0 x 10-7 seconds? The
mass of the electron at this lower speed is 9.5 x 10-31kg