This is not a homework question. I was preparing a problem sketch when I was questioned about a freebody diagram, and realized I didn't have an absolutely dead-certain answer. I know how to work the problem; I need help in documentation, that is, what the freebody diagram should look like. To make the question simple, I'll use a gedanken instance. Suppose a 100 kg person is standing on a 1 kg scale that is sitting on a small platform. The small platform is located in a part of the universe that has little gravity. The platform is accelerating upward at 10 m/s^2. I draw the freebody diagram for the scale as having 2 forces acting on it: 1010 N upward and 1000 N downward. The net force is 10 N which, for m = 1 kg, gives a = 10 m/s^2). That seems OK. Now, my conundrum. Should I draw the freebody diagram for the person as having a single upward force of 1000 N? As I said, I know how to solve the problem; I'm uncertain how to document it. As Helen Thomas likes to say, I'll have a follow-up question. Thanks.