Quick for middle school. waves, light and refraction

Atransverse wave is traveling on a string stretched along the horizontal x-axis. the equation for the vertical displacement y of the string is given by y = (1.8 x 10-3)cos[π(13x - 60t)], where all quantities are in si units. what is the maximum speed of a particle of the string

Which of the following is not am example of a polymer? protein nylon kevlar concreta

This is the substance(s) formed in a chemical reaction.