Here's the problem: An object is hung from a spring balance attached to the ceiling of an elevator cab. The balance reads 66 N when the cab is standing still. What is the reading when the cab is moving upward (a) with a constant speed of 7.6 m/s and (b) with a speed of 7.6 m/s while decelerating at a rate of 3.9 m/s2? In the sample problem given in my text, they state that for any velocity, you can just plug in the formula: Fn = m(g + a). Plugging in the numbers into this formula gets me a pair of wrong answers. However, a difference I noticed between the two problems is that their version doesn't give a speed and that in theirs, a man is standing on a scale while in the elevator, as opposed to an object hung from a spring balance. Why is my answer wrong, and how do I need to adjust my formula to obtain a correct answer?