Elevator Acceleration Calculations

[physics111]

I'm having a hard time with this question, I've done my share of research/computation and came up with an answer. Though I don't think the answer is correct and it might not even be what the question is asking for. Please help me out, thanks in advance!

Weight in an Accelerating Elevator


Take a bathroom scale and go into an elevator. Read your weight on the scale when the elevator is at rest. If the elevator is moving upwards or downwards you will observe that the reading on the scale changes. Record the maximum and the minimum values read on the scale. Using this information, find the elevators acceleration as it starts moving and as it stops. Make sure your result is given in the SI units for acceleration.
Include a diagram for each case, and show all your calculations.

MY attempt at a solution:
150lbs at rest=68.04kg=666.79N
160lbs at max=72.57kg=711.19N
135lbs at min=61.23kg=600.05N

Fnet=F-mg=ma

711.9N-666.79N=68.04a
45.11-68.04a
a=.65 m/s^2


600.05N-666.79N=68.04a
-66.74N=68.04a
a= -.98m/s^2

 

[nasu]

Did you measure these values yourself?
The calculation look OK. What bothers you?

 

[physics111]

Yes i measured these values myself quite a few times to be accurate, i don't know i just came up with this answer randomly I'm not exactly sure I am on the right track!

 

[merryjman]

The acceleration values sound reasonable for an accelerating elevator. And your calculations are correctly set up.

 

[nasu]

The calculation is OK as you did it.
Do you have a problem with the values for acceleration? What would you expect?