A 15 m long string of mass 1.8 kg is stretched such that the tension in the string is 25 N. A wave of frequency 20 Hz is sent through the string traveling to the right. Please show all work

a. find the speed of the wave

b. calculate the wavelength of the wave

c. write a mathematical expression for the displacement of the string particles knowing that their maximum displacement is 0.01m

d. calculate the displacement of a particle in the string at t= 10 s, when the wave is at x=0.5 m