Apparent Weight in an Elevator

[OP !!MhS7VrVrEwE No.3672662]

1. The problem statement, all variables and given/known data
While stationary on Earth you have a weight of 550N. When in an elevator that accelerates upward your weight temporarily becomes 590N. When descending, your weight temporarily becomes 510N. Find a) the acceleration you experience as the elevator moves up and b) the acceleration you experience as the elevator moves down.

2. Relevant equations
ΣF=m*a


3. The attempt at a solution
There are two forces acting on you in the elevator: the force due to gravity Fg, which acts downward, and the force of the floor on you Fn, which acts upward. According to Newton's 2nd law, the sum of these forces will equal m*a, so we can write
Fn - Fg = m*a
We know that Fg equals m*g, where g = 9.8m/s^2, so we can find the mass by dividing Fg by g, which yields about 56.1kg. Substituting in all of the known values and solving for a, we find that
for a)
a = (590−550)N/56.1kg = .713m/s^2
and for b)
a = (510−550)N/56.1kg = -.713m/s^2
The answer key and the others students got 10.5m/s^2 for (a) and 9.01m/s^2 for (b), which are the answers I got, plus g.
I'm pretty sure I'm the one who's wrong here, but I don't understand where I messed up. Help would be greatly appreciated.

[Anonymous No.3672715]

your not looking for a change in mass... m there should be in kg, not newtons... find out your mass then try again...

[Anonymous No.3672733]

Aspie is too socially retarded to ask his classmates. Ask 4chan instead.

[OP !!MhS7VrVrEwE No.3672747]

>>3672733
I did ask my classmates. How else would I have gotten their answers?
They couldn't figure out where the flaw in my reasoning was either, though. That's why I came here and to Physics Forums.
>>3672715
What are you talking about? My mass is in kilograms. It's 56.1kg, just like I posted in my original post.

[Anonymous No.3672771]

You are just reading the question wrong: Find the acceleration you ___experience___.
You experience gravity, as such, the answer is g + a (which you calculated).

[OP !!MhS7VrVrEwE No.3672780]

>>3672771
Ah. That makes sense. Thank you kindly, Anon.