Suitcase in elevator - Find pressure on the floor

[IAmSparticus]

1.A suitcase (mass m = 16 kg) is resting on the floor of an elevator. The part of the suitcase in contact with the floor measures 0.50 m by 0.14 m. The elevator is moving upward, the magnitude of its acceleration being 1.40 m/s2. What pressure (in excess of atmospheric pressure) is applied to the floor beneath the suitcase?



2. P=F/A



3.
Force=ma = 16kg*9.1.4m/s/s=22.4
A= .5m*.14m= .07
F/A= 22.4/.07
P= 320 Pa
This is wrong, can someone tell me where I went wrong?

 

[rl.bhat]

Force on the suitcase in a descending lift is m*(g-a).