forces, please help?

Question

a 81.0 kg person is standing on a scale in an elevator. what is the apparent weight when the elevator is

(a) accelerating upward with an acceleration of 1.80 m/s^2?

(b) moving upward at a constant speed?

(c) accelerating downward with an acceleration of 2.00 m/s^2?

i really am stuck. please help me. i don't know how to do this!!

please, Please, PLEASE help me!!!

thank you!

Answer 1

F=m*a

a)

Since the acceleration is upward, it increases the force on the scale per
F=(81*(9.81+1.80))
=940 N

b) At a constant speed, the only force is due to gravity
F=81*9.81
=795 N

c)
Downward reduces the Force on the scale by
F=81*(9.81-2.00)
=633 N
j

Answer 2

F+N=mA you need to find A in each part of the question
A= delta v/ delta t
if we put upward as positive then
A=m.g