Resistance force the drive has to overcome, such as friction forces ( see Calculation of "sliding" or "rolling resistance force" ).
In a lifting ( Hoist ) application F = Weight - Counter Weight + Friction Forces.
The traveling velocity of the load in feet per minute.
To calculate the velocity based on wheel, drum, sproket pitch diameter and rotational speed ( rpm ) see "Linear Velocity" calculation.
The overall efficiency consists of the driving unit ( Gearbox ) and the driven unit efficiency ( such as the chain or belt stage efficiency etc. )
see "Overall Efficiency" calculation
Power Required for Linear Motion
Variables   Units
FL Resistance force load lb
v Linear velocity fpm
ηT Overall efficiency %
PX Power hp