# Box hanging from a rope, need to know the force.

1. Feb 9, 2010

### dmdmm

A 23 kg box hangs from a rope. What is the tension in the rope if the following are true?

a)The box is at rest?
b)The box moves up at a steady 5.0 m/s?
c)The box has Vy = 5.0 m/s and is speeding up at 5.0 m/s^2?
d)The box has Vy = 5.0 m/s and is slowing down at 5.0 m/s^2

I have gotten a) = 225.4N. Because acceleration is 0. I do not know how to go about solving the other three parts though.

I know the force of gravity is acting on the box in addition to the tension force.

For b):
Since velocity is constant, I would think that the forces would be in equilibrium. But apparently I am wrong. I really have no idea how to solve this.

Any help at all would be appreciated.

2. Feb 9, 2010

### dmdmm

I figured it out. Now I feel stupid. Since acceleration is 0 (constant velocity), there would be no change in the force. So for b) the answer would still be 225.4N.

3. Feb 9, 2010

### PhanthomJay

This is good, now try 'c' and 'd' using Newtons 2nd law. Welcome to PF!

4. Feb 10, 2010

### dmdmm

Thanks.

Yeah, sorry I never replied back last night. But I did get the right answers. As soon as I figured out what was going on, everything just clicked.

What I was doing wrong for c and d was that I wasn't accounting for the the change in force. I just found the force with those particular amounts of acceleration.