Weighing yourself in the elevator

[test2morrow]

Need help:Weighing yourself in the elevator-acceleration problem

Homework Statement

If you stand on a spring scale in your bathroom at home, it reads 600N, which means your mass is 60kg. If instead, you stand on the scale while accelerating at 2 m/s^2 upward in an elevator, what would the scale read?

a. 120N
b. 480N
c. 600N
d. 720N

Homework Equations

W=mg

The Attempt at a Solution

So I asked my professor this question and he came up with some complicated answer that I didn't really understand. My own logic was that W=mg, W=60kg * (2m/s^2+9.8m/s^2), W=720N which is the correct answer. However, this is not the same steps the professor used which was something like F=N-W=ma and he did some subtraction work and somehow got 720N.

So can somebody explain to me the correct way to solve this problem?

 

[LowlyPion]

Homework Statement

If you stand on a spring scale in your bathroom at home, it reads 600N, which means your mass is 60kg. If instead, you stand on the scale while accelerating at 2 m/s^2 upward in an elevator, what would the scale read?

a. 120N
b. 480N
c. 600N
d. 720N

Homework Equations

W=mg

The Attempt at a Solution

So I asked my professor this question and he came up with some complicated answer that I didn't really understand. My own logic was that W=mg, W=60kg * (2m/s^2+9.8m/s^2), W=720N which is the correct answer. However, this is not the same steps the professor used which was something like F=N-W=ma and he did some subtraction work and somehow got 720N.

So can somebody explain to me the correct way to solve this problem?

That works too of course.

The 60 kg student is accelerating upward at 2 m/s². The Normal force of the student less the gravitational weight must yield an m*a of the same acceleration as the floor.
N is what the spring will register and rearranging that normal force = m*a + W = m*(g + a)

Your way works fine as well.