Question

The maximum tension a wire of mass density 0.015g/cm can support without breaking is (a little bit more than) 400N. a) (5 points) You clamp down the ends of 150 cm of this wire and then pluck it. As the wire vibrates you start to increase the tension in the wire. What (lowest) note will be heard right before the wire breaks? b) (5 points) You place another piece of the wire (150 cm) between the clamps and set the tension to 200N. Where do you have to place your finger on the wire so that you hear the same note?

Answer 1

a) f = V/2L = 1/2L squareroot T/mu = 1/2 times 1.5 squareroot 450/0.0015 kg/m = 172Hg b) 172 = 1/2L squareroot 200/0.0015 L = 0.94 at 94cm.