(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 57.0 kg girl weighs herself by standing on a scale in an elevator. What is the force exerted by the scale when the elevator is descending at a constant speed of 10 m/s?

What is the force exerted by the scale if the elevator is accelerating downward with an acceleration of 2.0 m/s2?

If the elevator's descending speed is measured at 10 m/s at a given point, but its speed is decreasing by 2.0 m/s2, what is the force exerted by the scale?

2. Relevant equations

F=ma, Fs-W=ma

3. The attempt at a solution

I got the first part, 9.8(57) = 558.6 N.

For the second part I used Fs-W=ma, Fs - 558.6 = (57)2, Fs= 672 N. But that was wrong...?

For the 3rd part, I used F=ma, but F= 57 (-2) = -144 N, and that wasn't right either.

Help!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Another force problem

**Physics Forums | Science Articles, Homework Help, Discussion**