[填空题]
1.Discuss the differences between traveling waves and standing waves
2.A 45cm guitar string fixed at both ends is raised and released so that it vibrates at its fundamental mode. The midpoint of the string passes through its equilibrium position 475 times in one second. Estimate the speed of the wave on the string.v= $m\,s^{-1}$
3.The guitar string is now gently touched 15cm from one end such that a node is created at that point, but the entire length of the string still oscillates. Calculate the frequency of the sound generated.
