During heavy lifting, a disk between spinal vertebrae is subjected to a $5000$ N compressional force.

$($a$)$

What pressure $($in Pa$)$ is created, taking the disk to have a uniform circular cross section $1\mathrm{.}80$ cm in radius?

Pa

$($b$)$

What deformation $($in cm$)$ is produced if the disk is $0\mathrm{.}790$ cm thick and has a Young's modulus of $1\mathrm{.}5109$ N$/$m$2?$