Answer:

Explanation:
We need to find the frequency of green light having wavelength o
. It can be calculated as follows :

So, the required frequency of green light is equal to
.
In 6 secs, the dog covers-
S=vt
8.9*6 = 53.4 m.
In the same time, the cat covers, 53.4-3.8 = 49.6 m.
Thus, speed of the cat, v= s/t,
= 49.6/6 = 8.267 m/s
The astronauts hearing the rocket landing is inaccurate. Sound waves can’t travel through a vacuum, meaning a place where there are no air particles. They are mechanical waves and require a medium to travel through. So, because there is no air in space, you can’t hear anything.
Jet stream<span>ˈjet ˈˌstrēm/</span>noun1.a narrow, variable band of very strong, predominantly westerly air currents encircling the globe several miles above the earth. There are typically two or three jet streams in each of the northern and southern hemispheres.
(credit to google)