A ski gondola is connected to the top of a hill by a steel cable of length 720 m and diameter 1.3 cm. 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 14 s for the pulse to return.
What is the speed of the pulse?
What is the tension in the cable?
Physics - drwls, Friday, December 3, 2010 at 12:30am
The wave speed is 2*720/14 = 103 m/s
103 m/s = sqrt(T/a)
where a is the mass of cable per length. You will need the density of steel and the cable radius to get a.
a = pi (D^2/4)*(steel density)
Make sure it is in kg/m
Then solve for T , which will be in Newtons