# Homework Help: Newton's Second Law Problem

1. Oct 29, 2008

### swede5670

1. The problem statement, all variables and given/known data
A 60.0 kg person stands on a scale in an elevator. (solve in Newtons)
What does it read when the elevator is accelerating upward at 3.5 m/s2?
What does it read when the elevator is accelerating downward at 3.5 m/s2?

2. Relevant equations
Fnet = ma

3. The attempt at a solution
First I set up the equation
Fnet = ma
(588.6 + X) = 60 x 3.5
588.6 + X = 210
X = -378.6
So then I plugged in X
588.6 + -378.6 = 210
210N

I know that this is wrong but I'm not sure what I need to fix/change

2. Oct 29, 2008

### Rake-MC

I would look at it a lot more simply: You know that gravity applies an acceleration to masses (9.8 ms-2).

If the elelavtor is not moving, that's all the acceleration a body feels, however when the evelator is accelerating upwards, a body feels this acceleration as well as the acceleration due to gravity.

I would simply sum up the gravitational acceleration and acceleration due to the elevator and then apply F = ma.