$4.(15$ pts total$)$ A person is using both hands to hold a box on its two handles, with a posture illustrated by the figure below..

Assume the person's body dimensions are all at the level of a $50$th percentile female.

i$.$ What is the length from the elbow to the handle? What is the length from the shoulder to the elbow? $(3$ pts$)$

ii$.$ The mass of the box is $8$ kg $($the mass center is located in the middle of the box$),$ the mass of a lower arm plus a hand is $1\mathrm{.}4$ kg $($the mass center is located in the middle of the segment$),$ an upper arm weighs $2$ kg $($the mass center is located in the middle of this segment$),$ and the total mass of the head and torso is $28$ kg $.$ Use $\backslash (\backslash$mathrm$\{$g$\}=10\backslash$mathrm$\{$~N$\}/\backslash$mathrm$\{$kg$\}\backslash ),$ and $1$ inch $=2\mathrm{.}54$ cm $.$ How large is the force $($in Newtons$)$ exerted by the back muscles at the L$5/$S$1?$ How large is the compression force at the L$5/$S$1?(12$ pts$)$