How Long Does It Take a Pulse to Travel Across a Ravine When a Rope is Plucked?

[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?

Please Help me out

 

[LowlyPion]

http://en.wikipedia.org/wiki/Wave#Propagation_through_strings

 

[dsptl]

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

help me out

 

[hage567]

Show your calculation so we can see what you did.

 

[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

 

[LowlyPion]

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

 

[dsptl]

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