Astring is strung horizontally with a fixed tension. a wave of frequency 90 hz is sent along the string, and it has a wave speed of 55.1 m/s. then a second wave, one of frequency 180 hz, is sent along the string. what is the wave speed of the second wave?

wave speed of the second wave 55.1 m/s

Explanation:

The wave speed of the second wave will going to be same i.e 55.1 m/s. As speed of wave is dependent on the medium and here in this case medium is remain same for second wave also i.e string only, no change in the medium noticed, therefore speed of second wave still remain same i.e 55.1 m/s.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.