Physics
posted by Bill .
Calculate the force on an electron (qe = 1.6 x 10^19 C) in each of the following situations:
a.) moving at 2.0% the speed of light and perpendicular to a 3.0 T magnetic field
b.) 3.0 x 10^6 m from a proton
c.) in Earth's gravitational field at the surface of Earth

(a) Lorentz force F =q•v•B•sinα.
α= 90º, q=e,
F =1.6•10^19 •0.02•3•10^8•3 =
(b) F=k•q1•q2/r² =
9•10^9•(1.6•10^19)²/3•10^6 =
(c) F =G• m•M/R².
m(electron) = m = 9.1•10^31 kg
the gravitational constant G =6.67•10^11 N•m²/kg²,
Earth’s mass is M = 5.97•10^24 kg,
Earth’s radius is R = 6.378•10^6 m. 
Awesome, thanks Elena!