That should be the Grasslands ?
<span>The distance between wave crests is called wavelength. It is a characteristic shared by waves of all kinds, including ocean waves and sound waves. Wavelength is measured from the highest point, or summit, of one wave's crest to the summit of the next wave's <span>crest</span></span>
<span><span>hope this helps</span></span>
Answer:
a.14 s
b.70 s
Explanation:
a.Let the sidewalk moving in positive x- direction.
Speed of sidewalk relative to ground=
Speed of women relative to sidewalk=v=1.5m/s
The speed of women relative to the ground

Distance=35 m
Time=
Using the formula
Time taken by women to reach the opposite end if she walks in the same direction the sidewalk is moving=
b.If she gets on at the end opposite the end in part (a)
Then, we take displacement negative.
Speed of sidewalk relative to ground=
Speed of women relative to sidewalk=v=-1.5 m/s
The speed of women relative to the ground=
Time=
Hence, the women takes 70 s to reach the opposite end if she walks in the opposite direction the sidewalk is moving.