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THERMO Spoken Here! ~ J. Pohl © ~ 2017 www.ThermoSpokenHere.com (C1900-128)

3.04 Work Considerations

Events of a man are described below. In each case the event is "incremental in time." Before the event is "no motion," "motion and the event commence, procede," then "everything stops." Scenarios of the events make this clear. We study the man, modeled as a BODY (of mass, m). The work of each event (as defined by physics) is our consideration, only.

1) "Pullup:" Initilly a man (of mass, m) hangs vertically and motionless from a horizontal bar. The event commences as the man pulls himself upwade. Finally the man's chin is motionless just above the bar. The elevation change of the man is "H."

"Pullup"

pullup
"Stairs"

walk-up-stairs
"Rope Climb"
rope-climb

What is the work of the man? rope-climb

2) a "walk-up-stairs:" walk-up-stairs

The art work depicts a man ascending a flight of stairs. Our event is that the man ascends the entire flight - to the top. The elevation change of the man is H.

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A "rope climb:" rope-climb

The art work depicts a man ascending a flight of stairs. Our event is that the man ascends the entire flight - to the top. The elevation change of the man is H.

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A "pulley lift:" pulley-lift

The scenario is a man uses his physical strength with a rope and pulley to elevate a mass lifted is H.

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A "pulley self-lift;"

self-lift In the simplest case, a man might use a rope and pulley to (by his own physical effort) raise himself to an elevation change, H.

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Compound "pulley self-lift;" compound self lift The art work depicts a man ascending a flight of stairs. Our event is that the man ascends the entire flight - to the top. The elevation change of the man is H.

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