# Does decreasing the length of the line between a harness and zip wire increase the velocity at which you travel?

My friend is an instructor at an outdoor adventure centre which has lots of zip wires. The instructor's harness has a shorter line that attaches to the zip wire than the normal harness does and she claims that you go much faster with it. Is this true? I can't think of any reason as to why it would be MUCH faster but apparently their speed gun proved it.

Edit: Diagram for clarity

• Did they prove it with different people in the same harness, or same person in different harnesses? If so, I can think of 2 possibilities. 1) long line could lead to a greater lag angle (how far behind the trolley the person is), which could cause binding of the trolley's pulleys. 2) the line itself has huge wind drag, which is unlikely to be a significant cause. – Carl Witthoft Feb 6 '14 at 19:51
• Could you add a diagram? – Fergus Feb 6 '14 at 19:58
• @CarlWitthoft I thought the angle could be different and therefore make a difference but after thinking about it some more, I'm not actually sure there would be a difference in the angle. Somebody should work out the math to see if there is any difference in the angle. – Brandon Enright Feb 6 '14 at 20:46
• Added a diagram for clarity. I don't think anyone has been speed checked in both harnesses so technically no valid conclusions can be drawn. It's more of the average speed in the shorter harness is more than the average speed in the longer one and just the word of the instructors who have used both. The only thing I can think of as to why is could be quicker would be due to better/less worn pulleys in the instructor harness – Josh Roberts Feb 6 '14 at 20:55
• In my experience of these, there is more friction in the trolley than on the person, and there is some swinging backward and forward. A shorter line will make more rapid swinging, and maybe a quicker restoration of the sliding down conditions? – Joce Jun 12 '14 at 12:38