Posted by Wenmar on .
I have trouble with these 2 problems, can anyone assist me to answer them?
18) What is the speed of a periodic wave disturbance that has a frequency of 3.50 Hz and a wavelength of 0.700 m?
21) A periodic longitudinal wave that has a frequency of 20.0 Hz travels along a coil spring. If the distance between successive compressions is 0.600 m, what is the speed of the wave?

Waves (Physics) 
drwls,
18) Multiply wavelength by frequency.
21) 0.600 is in this case the wavelength. Once again, multiply ot by the frequency to get the wave speed.