# No mass for mass per unit length

Tags:
1. Nov 2, 2015

### nanocreation76

1. The problem statement, all variables and given/known data
A ski gondola is connected to the top of a hill by a steel cable of length L and radius R . As the gondola comes to the end of its run, it bumps into the terminal and sends a wave pulse along the cable. It is observed that it took T seconds for the pulse to return.
What is the tension in the cable?

2. Relevant equations
v=sqrt(T/mu)

3. The attempt at a solution
With the given information I can calculate velocity and volume of the cable. I can't figure out how to turn that into tension. There's no given mass for calculating mass per unit length, and I can't figure or find any other way of calculating tension.

2. Nov 2, 2015

### SteamKing

Staff Emeritus
Since you know the material of the cable (steel) you should be able to calculate how much mass a cable with the given dimensions would have. Knowing the length will give you an expression for μ for the cable. You know how long the cable is and how long it takes for the pulse to travel along the length.

You have to make an attempt at seeing if some of these dimensions cancel, and you can come up with an expression for the tension in the cable. It may not be a number which you obtain, but another formula. You won't know for sure until you start writing equations down.