(I)
\Radius of the pulley is
inches.
Angle of each rotation is
.
Angle of
revolution is
radians.
Linear speed
.
Substitute
,
and
in
.

in/min.
(II)
\Radius of the pulley is
inches.
Angle of each rotation is
.
Angle of
revolution is
radians.
Substitute
,
and
in
.

in/min.
(III)
\Radius of the pulley is
inches.
Angle of each rotation is
.
Angle of
revolution is
radians.
Substitute
,
and
in
.

in/min.
Pulley has the highest linear speed in Scenario III.
\Scenario III would be the fastest method to use to lift a distance of 15 feet fastest.
\Scenario III would be the fastest method to use to lift a distance of 15 feet fastest.