# Force / Tension Question

1. Oct 13, 2005

### amcavoy

This isn't a HW question, just a thought. If I held a rock in my hand and connected it to a rope which I held in my other hand, then dropped it off of a cliff, how heavy would it "feel" when the slack ran out?

I know that the force is the same the entire way down, but when the slack ran out there would be a tension force going upwards towards me. However, it is obvious that it has to do with more than the acceleration, which would assume the tension of the rock just sitting there, not having been dropped.

Is it something to do with momentum? I know p=mv, so If I replaced v with at, I come up with p=m(at). How can I find the tension knowing the momentum?

Alex

2. Oct 13, 2005

### stmoe

I think I know what you're getting at, in which case I'd suggest also seeing that p = (ma)t , now, the question of what would it 'feel' like would kind of be a question of what exactly you'd consider as the 'feel'. Personally, I'd say that what it feels like would be the force it exerts on the hand. .. and then to put it into a perspective for others I'd take it as a weight .. and thus I could do mass based on 9.81 for the a. (which, if its free falling really tells a lot)

3. Oct 13, 2005

### amcavoy

By feel I mean the tension at the moment the rope runs out of slack and the rock stops its freefall (stopped by the rope).

Thanks,

Alex