# Quantitative Problem 20.10

1. Jan 19, 2009

### dsptl

A rope with a total mass of 25.0 kg is tied to a tree on one side of a 125 meter wide ravine, and you're pulling on the other end of the rope with a force of 415 N. If you pluck the rope, how long will it take the pulse to travel across the ravine to the tree?

2. Jan 19, 2009

### LowlyPion

3. Jan 19, 2009

### dsptl

yes I have already tried that and I got 2.74sec but in MasteringPhysics it gives me wrong.......

help me out

4. Jan 19, 2009

### hage567

Show your calculation so we can see what you did.

5. Jan 19, 2009

### dsptl

So, u = 25/125 = 1/5 kg/m
So, T = sqrt(415 kg m/s^2 / (1/5 kg/m)) = sqrt( 415*5 m^2/s^2) = sqrt(2075) m/s = 45.55 m/s

then I did t = d/v = 125m/45.55m/s = 2.74sec

6. Jan 19, 2009

### LowlyPion

Your calculation looks correct. I can only suggest that there is a question of precision in accepting your answer.

7. Jan 20, 2009

### dsptl

i have only one trial left and i don't wanna take risk...please suggest me an answer