【Brainstorm】What a tough job for the messenger
Thread Content
A column 100 meters long is moving forward. A messenger walks from the back of the column to the front, and then from the front back to the back; during this time, the column moves exactly 100 meters, assuming that both the speed of the column and the speed of the messenger remain constant! 1. Ask how many meters the messenger has walked. 2. What if the messenger starts at the front of the line?
With constant speed, it’s impossible to move from the back of the line to the front.
200 meters. At the front as well.
The speed remains constant; it doesn’t mean that the speed of the messenger is the same as that of the troop.
200m, and at the front it’s also 200m
Relative velocity: one involves subtracting speeds, and the other involves adding speeds; they cancel each other out~