Alright, this problem has been driving me into a confused rage. The wave is moving in an upward direction so particle A should be moving up as well, right? But every single website I've used to study claims that it's moving in a downward direction. How?
The Attempt at a Solution
This might be way of the mark, but maybe the phrase "next instant of time" is throwing me off? Does that mean the next cycle or the next nanosecond or what?[/B]