Workout problem $1[10$pt$]$

A male worker, $5$ ft $8$ in tall and $220$ lbs $,$ is holding a $20$ kg tool with both hands. His lower arm is inclined at $45$ degrees from the horizontal and upper arm is inclined at $45$ degrees from the horizontal. $($A complete answer would include stating assumptions, drawing the sign convention, free$-$body diagrams, and showing all calculations$)$

$($A$)$ Determine the static external forces and moments at the elbow and shoulder.

$($B$)$ What percentage of the male population could maintain this posture for a short time?

Assume population elbow strength has the following distribution:

Flexion: mean $=45Nm$ and std$.$dev. $=10Nm.$

Extension: mean $=46Nm$ and std$.$dev. $=15Nm.$

Assume population shoulder strength has the following distribution:

Flexion: mean $=62Nm$ and std$.$dev. $=17Nm.$

Extension: mean $=67Nm$ and std$.$dev. $=15Nm.$