# What kind of forces would follow only the second part of shell theorem? [duplicate]

What kind of forces would follow only the second part of shell theorem? General expression of a force which would cancel out inside a uniform hollow shell. What about any closed surface?

• What are you asking? Commented Apr 18, 2015 at 19:25
• Newton proved that within a spherical shell, one may disregard the gravitational force due to mass of the shell.Garavity here follow s inverse square law . What other hypothetical law could a force follow to achieve the same result?
– user78187
Commented Apr 18, 2015 at 19:33
• you could look at the derivation of shell theorem for this answer.for any irregular body it is simpler to consider it in terms of shells or cylinders and use gauss' law to get field to get force Commented Jun 2, 2015 at 2:25
• Possible duplicate: physics.stackexchange.com/q/318135/2451. Commented Jul 15, 2018 at 17:25

I don't think that there is a general expression but most of the $1/r^2$ proportional following forces are cancelling in a sphere and for electrostatic force they can be cancelled inside any closed conductor where charges can redistribute.