a boulder drops in the water and creates a wave with a period of 2 s/cycle and a wavelength of .75 m/cycle. how fast is the wave moving

he is very short, and he can only reach halfway up on the elevator buttons. but on a rainy day, he has his umbrella with him, and he uses it to poke the button at the top.

1. b.

2. d.

3. a.

5. d.

6. c.

these are the only ones that i know, i hope this , and good luck.