EK Physics #662

[mr chievous]

---

Members do not see this ad.

A wave is sent down a taught rope. Which of the following will change the velocity of the wave?

The answer is "changing the tension in the rope" which is pretty obvious, but why is "changing the length of the rope" incorrect? I thought TBR said v = (T x length/mass)^1/2 when determining wave speed. One of TBR's wave passages even said changing the length would change the velocity.

 

[cheesier]

length/mass is a function of the density of the rope. If you were to stretch the rope and keep the same mass you're right that it would change the velocity, but that's not what the answer choice says. It just says use a longer rope. If you use a 10 vs 20 foot version of the same rope, the length and the mass are both changing, so velocity doesn't change.