I am trying to understand a diagram I have of a gymnast hanging from a bar. She weighs 50kg and is not swinging, just hanging. In the diagram it has her weight as 500N (using 10/m/s/s for gravity * 50kg) but the bar she is hanging from has an upward arrow with 550 N next to it. I interpret this to mean that the bar is exerting 550N of upward force against the gymnast. However I thought for every action there is an opposite reaction. Wouldn't this mean the bar is only exerting 500N up from the gymnast given here downward force is 500N ?
The object of the diagram is for people to interpret the net force on the gymnast.
550N - 500N = 50N
or 500N - 500N = 0N