# Homework Help: A question with masses and distance to travel, find the time to travel so far

1. Oct 21, 2007

### maphco

1. The problem statement, all variables and given/known data
Jane wishes to quickly scale a slender vine to visit Tarzan in his treetop hut. The vine is known to safely support the combined weight of Tarzan, Jane, and Cheeta. Tarzan has twice the mass of Jane, who has twice the mass of Cheeta. If the vine is 60m long, what minimum time should Jane allow for the climb?

2. Relevant equations

3. The attempt at a solution
Mass of Tarzan = 2 * Mass of Jane = 4 * Mass of Cheeta
Mass of Jane = 2 * Mass of Cheeta
Mass of Cheeta = ?

Length of vine = 60m

Can you guys help me suck out any more relevent information, or assumptions, from this question that I've missed? I like to solve problems on my own, even if it takes me a month like one particular question.. I just want a heads up on what I'm missing.

2. Oct 21, 2007

### Hootenanny

Staff Emeritus
I think the question is hinting at some use of Newton's second law...

3. Oct 21, 2007

### maphco

Is there a way that I can incorporate the Law of Conservation of Energy into this question?

4. Oct 23, 2007

### Hootenanny

Staff Emeritus
I don't think so...

5. May 30, 2009

### DB Katzin

the vine can support the weight of Jane + Tarzan = 2xJane + cheeta = 1/2xJane so the vine can support the weight of 3 and 1/2 Janes. So I think the question is asking how fast does jane have to climb so her weight is increased by a factor of 3.5. Alternatively, if jane is starting on the ground than she has to accelerate to move up the rope. The max force she can apply during the climb is 3.5 her weight where her weight is her mass at 1g or the rope breaks.

Last edited: May 30, 2009
6. Nov 15, 2010

F=ma?