posted by Drew on .
A steel cable is stretched across a gorge. The cable is 190 m long and has a mass of 44 kg. When one end of the cable is struck with a hammer, a wave pulse travels down the cable, reflects at the far end, and is detected back at the first end 14 s later. What is the speed of the wave?
I couldn't calculate force in this which i believe is necessary
The wave takes 7 seconds to cross the gorge. The average speed of the wave is 190/7 = 27.1 m/s.
You don't need the mass information. There is a formula for wave speed in terms of cable tension and mass per length, but you don't need to use it here. Actually, the wave speed will vary with the position and cable slope along the length.