A $185-kg$ object and a $485-kg$ object are separated by $3\mathrm{.}10$ m $.$

$($a$)$ Find the magnitude of the net gravitational force exerted by these objects on a $43\mathrm{.}0-kg$ object placed midway between them.

$($b$)$ At what position $($other than an infinitely remote one$)$ can the $43\mathrm{.}0-kg$ object be placed so as to experience a net force of zero from the other two objects? m from the $485$ kg mass toward the $185$ kg mass