You are holding a string tied to a lamp post 15 m away. You pull the string so that it has a tension of 1.5 N and a mass density of 0.0045 kg/m. You shake the end of the string at 4 Hz. What is the wavelength of the wave you generate in m? You now take three pieces of string from the previous problem and tie two of them together to make a string of double the mass density. You tie the single string and double string together and to two lamp posts that are 40 m apart as seen below. The interface is centered between the posts and the tension is 1.2 N. You briefly shake the string interface at 5 Hz.

By how many seconds does it win the race?