What is the tension in a climber's rope while rappelling down a cliff?

[lacar213]

Homework Statement

A climber of mass 64.8 kg is rappelling down a cliff, but has momentarily paused. She stands with her feet pressed against the icy, frictionless rock face and her body horizontal. A rope of negligible mass is attached to her near her waist, 1.04 m horizontally from the rock face. There is 5.25 m of rope between her waist and where the rope is attached to a chock in the face of the vertical wall she is descending. Calculate the tension in the rope.

Homework Equations

FL + (-mg cos theta) = 0
t + (-mg) = ma

The Attempt at a Solution

I think that I have to find the angle by using cos = adj./hyp. but that answer comes out very small and doesn't seem correct
or should I find the acceleration first and use t + (-mg) = ma

 

[tiny-tim]

FL + (-mg cos theta) = 0
t + (-mg) = ma
…
I think that I have to find the angle by using cos = adj./hyp. but that answer comes out very small and doesn't seem correct
or should I find the acceleration first and use t + (-mg) = ma

Hi lacar213!

(It would help if you actually showed us what you did … for example, what is your theta? )

I don't understand what you think the acceleration is … the rock isn't falling, is it?

 

[HallsofIvy]

1) What isthis titled "airplane at constant velocity"?

2) She has "her body horizontal"? ?? Why?

 

[lacar213]

1) What isthis titled "airplane at constant velocity"?

2) She has "her body horizontal"? ?? Why?

"airplane at constant velocity" was the section in my book where this problem is from

 

[lacar213]

Hi lacar213!

(It would help if you actually showed us what you did … for example, what is your theta? )

I don't understand what you think the acceleration is … the rock isn't falling, is it?

The only thing I tried was finding the angle - but that doesn't seem correct, I don't know what to do from there. The equation going along with this problem is looking for LIFT which has nothing to do with the problem given. The tension equation contains acceleration
T + (-mg) = ma