A 75kg man stands in an elevator. What will be the force the elevator exerts on him when:
a) the elevator is at rest
b) the elevator is moving upward with a uniform acceleration of 2.0m/s^2
c) the elevator is moving downward with a uniform acceleration of 2.0m/s^2.
Fg = mg
FNet = m(a)
The Attempt at a Solution
I got the following answers that matched the ones on my worksheet:
a) = 735.75 N [up]
The other two I got from just randomly pluging and adding/subtracting the acceleration of gravity with the uniform acceleration of the elevator.
However, I don't understand what I did and WHY this is the answer. I am the type that doesn't just take the answer as correct from getting it right, but until it makes sense to me..
b) F = (75)(9.81 + 2.0)
c) F = (75)(9.81 - 2.0)