# Dynamics: Newton's Second Law_Tension_1

1. Jan 8, 2015

### yandereni

1. The problem statement, all variables and given/known data

*Note: I'm really stuck in this part of Newton's 2nd Law so I may be asking a few more questions after this to practice for our upcoming examinations.

A cable supporting a 2125kg elevator has a maximum strength of 21750N. What maximum upward acceleration can it give without breaking?

2. Relevant equations

1. Forcevertical= Forcetension + Forcegravity
2. Force= (mass)(acceleration)

3. The attempt at a solution
What I did is:
Forcevertical=21750N + [(-9.8m/s2)(2125kg)]
Forcevertical=925N

Then after solving the first part, i used the 2nd equation then did this:
925N = (2125N)(a)
a = 0.435 m/s2

I'm not quite sure if I'm right in this problem.

2. Jan 8, 2015

### Staff: Mentor

Method looks right. I've misplaced my sliderule at the moment, so haven't checked your multiplication answer. :)

3. Jan 8, 2015

### Cake

The calculations are correct. You did nothing wrong that I ca tell.

4. Jan 8, 2015

### yandereni

thank you for checking it! but i dont know why my classmates keep on proving me wrong though

5. Jan 8, 2015

### Cake

Well the question is basically asking how fast you can move the elevator up with respect to the mass of the elevator. So the answer makes sense. If they're arguing with it I'm curious as to what they're doing.

6. Jan 8, 2015

### yandereni

Thank you! I thought i did it wrong but it was right all along. :)

7. Jan 8, 2015

### ubergewehr273

Well, even I seem to get this answer only.

8. Jan 8, 2015

### Maged Saeed

I think you are right ,,