Which of the following scenarios describes an object being acted on by a conservative force?

A woman hikes up a mountain to a point 20 feet above ground.
A dishwasher was pulled up to a window by a rope, using a pulley system.
A feather falls from one end of a tube to the other inside a vacuum.
A puck glides across and slowly comes to a stop on an ice rink.

Question

Which of the following scenarios describes an object being acted on by a conservative force?

A woman hikes up a mountain to a point 20 feet above ground.
 A dishwasher was pulled up to a window by a rope, using a pulley system.
 A feather falls from one end of a tube to the other inside a vacuum.
 A puck glides across and slowly comes to a stop on an ice rink.

kekeman · Answer

I think it is " A feather falls from one end of a tube to the other inside a vacuum."

Rigo · Answer

and why do you think that?