Question

A particle with a charge of

−60.0 nC

is placed at the center of a nonconducting spherical shell of inner radius 20.0 cm and outer radius 22.0 cm. The spherical shell carries charge with a uniform density of

−1.04 μC/m³.

A proton moves in a circular orbit just outside the spherical shell. Calculate the speed of the proton.

Part 1 of 6 - Conceptualize:

Draw a picture of the physical setup described in the problem statement. Your picture should look something like the one below.

A particle of charge q = −60.0 nC lies at the center of a nonconducting spherical shell of inner radius r₁ = 20.0 cm, outer radius r₂, and charge density ρ. A proton moves in a circular orbit just outside of the spherical shell.

Imagine the proton in a circular orbit just outside the spherical shell. All of the charge inside the orbit of the proton is negative, so there will be an inward-directed force on the orbiting proton.

We'll use the symbols q for the charge at the center of the spherical shell,

r₁

and

r₂

for the inner and outer radii, respectively, of the spherical shell, ρ for the charge density on the spherical shell, and

m_p

and e for the mass and charge, respectively, of the proton.

(1) Let us focus on the proton in orbit just outside the spherical shell. Which combination of analysis models below correctly describes the proton in this situation and will be of most use to us for solving this problem?

particle in a field (electric), particle under a net force, and particle in uniform circular motion particle in a field (electric),

particle in equilibrium, and particle in uniform circular motion    

particle under a net force and particle in uniform circular motion particle in a field (electric),

particle under a net force, and particle under constant acceleration

none of the above

Answer 1