Question

For questions 9 through 11, refer to the figure below. Boat going forward, output distance at the bottom
9. Which arrow represents the input force? Label it on the figure.
10. Which arrow represents the input distance? Label it on the figure.
11. Which arrow represents the output force? Label it on the figure.

Answer 1

I don’t have the actual picture you’re looking at, so I’ll describe where to put the labels and why. If you can upload the figure I’ll mark them precisely.

General rule to identify each:
- The input force is where the person (or agent) applies a force to the machine (e.g. the hand pulling the rope).
- The input distance is the distance the person’s point of application moves (e.g. how much rope is pulled).
- The output force is the force the machine exerts on the load (e.g. the force pulling the boat forward).
(You already noted the output distance is the bottom arrow showing how far the boat moves.)

Answers to label on the figure:
9) Input force — label the arrow at the person’s hand (the arrow on the rope where it is being pulled) as Fin (or “input force”).
10) Input distance — label the arrow along the rope showing how far the rope is pulled as din (or “input distance”).
11) Output force — label the arrow on the boat pointing forward (the arrow showing the force on the boat) as Fout (or “output force”).

Quick justification: Fin · din ≈ Fout · dout (neglecting losses), so Fin is where the operator pushes/pulls, din is how far that point moves, and Fout is the force on the boat that produces the bottom arrow’s displacement.