$6)$ Consider the worker on the ground $($not shown in photo$)$ lifts the cases $(10$ in $.$ high and $10$ in $.$ deep, $30$ lbs $)$ similarly to the worker in the truck. He lifts it from the ground and lifts it to the flat bed of the truck where another worker $($shown here$)$ will position it properly. Assume that the lift from the ground is fairly optimal, but that the reach onto the truck is fairly bad at $20$ inches $($i$.$e$,$ significant control is required$).$

a$)$ How many crates per minute can he load for an $8-$hour shift so as to be acceptable according to NIOSH guidelines?

b$)$ b$)$ Now redesign the job, so as to increase or maintain the expected quota of $10$ boxes per minute but still keep back strain to acceptable levels. Show that it is acceptable per NIOSH. snip