Rejected Physics Problems

[Borodog]

I wrote this problem for an upcoming test and rejected it as too hard. However, I figured someone around here might find it interesting.



What is x in terms of the length of the rope L, d, and delta-h?

PS. What is the tension in the rope?

[purnell]

I find it interesting, but it's been almost 20 years since I solved this kind of thing. Will it help me to review a statics textbook, or is there more to this than I'm seeing?

[almostbusto]

i am getting a degree in math this semester and i have no idea how to solve that problem. but i have never taken a physics course.

anyway, i just wanted to say you should post the solution in white. or PM it to me. i'd like to see how its done

if i had to guess... at deltaH=0 X=.5D at deltaH=H X=D from that i would just guess that X would move uniformly from .5D to D as H was lowered from h to 0. obviously that is way wrong though because the solution is very simple and doesn't use all the givens. so it certainly wouldn't be a rejected problem if i was right.

[BluffTHIS!]

Boro,

I too have forgotten everything I studied in college physics and so don't have an idea. However wouldn't the elastic properties of any particular rope also come into play here?

[slickpoppa]

[ QUOTE ]
Boro,

I too have forgotten everything I studied in college physics and so don't have an idea. However wouldn't the elastic properties of any particular rope also come into play here?

[/ QUOTE ]

I think we are assuming that the rope is inelastic, and therefore would not be taut if the weight were not hanging on it.

Anyway, I don't see how this is really a physics question since the main question (solving for x) depends completely on trig and not any physical laws. Though I will say that it is not an easy question. I'm sad to say that I'm going to have to sleep on it.

[zadig]

d - 1
x= --------------- + delta h
sqrt(L^2 - d^2)

[evank15]

It's really pretty sad I can't do this.

Probably one of the reasons I got a C in classical mechanics last semester. Although that class was a lot more about Langrangian mechanics than Newtonian mechanics.

I hate classical mechanics. I can do EM, (some)QM, Thermo, Astro/Cosmo etc etc, but give me a [censored] rope on a wall and I freeze up.

[Nielsio]

That's easy. x = 5.5cm.

[MaxWeiss]

Here's what I have so far. I can't figure how to relate H to delta-h or the change in length to the change in angles, which I could then use to relate to L-sub-one, which I (correctly???) believe is half of L. Am I even on the right track??? God it's been years since I took any physics or math. My head hurts... but it's a good hurt.

[thylacine]

It does not seem too hard for college(?) level. Maybe they thought the problem had just one small physics insight and then it was all trig.