A proton is launched from the surface of a 2.0 cm diameter glass
sphere that is charged to -25.0 nC. What is the speed of the
proton when it is launched so that it just escapes the influence
of the charge of the glass sphere? A 3.2 cm diameter plastic
sphere is charged to -19.0 nC. What orbital frequency must a
proton have to maintain a circular orbit around the sphere 2.4
mm above its surface? Two 18.0 cm diameter charged rings face
each other, 22.0 cm apart. The left ring is charged to + 40.0 nC
and the right ring is charged to + 15.0 nC. What is the force on
a + 0.50 nC charge placed at the mid point? A proton orbits a
negatively charged wire that has a linear charge density of 8.0
x 10 -9 C/m. What speed must the proton have to maintain a
circular orbit at 1.3 cm? For Further Reading