Question

Motion maps for two objects, Y and Z, are shown.

A motion map. The position line is a long black arrow pointing right with x as the reference point at left. Above the line are three dots, each with a vector pointed away from x back to back in a line labeled B. Above B, there are four dots, each with a shorter vector pointing away from x in a line labeled A starting closer to x .

At which time does Object Y pass Object Z?

2
3
4
5

Answer 1

I can’t be sure from the written description which track (A or B) is object Y and which is Z, and which dot is time 1 vs time 2, etc. Could you either

- tell me which label (A or B) is Y and which is Z, and whether the dots are times 1–4 left-to-right, or
- upload the picture?

If you’d like to figure it out yourself: the passing time is the time index at which the two objects’ dots are at the same position (a dot overlapping). Once I know which trace is Y and which is Z I’ll pick the correct time from 2, 3, 4 or 5.