Hi there!
The period of an orbit can be found by:

T = Period (? s)
r = radius of orbit (6400000 m)
v = speed of the satellite (8000 m/s)
This is the same as the distance = vt equation. The total distance traveled by the satellite is the circumference of its circular orbit.
Let's plug in what we know and solve.

I would say letter A to this because we need rain water for crops plants. Also we need it so that we can drink it. Its less great over sea because as it merge with the salt in the ocean it becomes less drinkable and less usable.
Answer:
v = 3×10^8 m/s
s= 384,400 km= 3.84×10^8 m/s
t = ?
v = s/t = 2s/t
t = 2s/v
t = (2×3.84×10^8) ÷ 3×10^8
t = 2.56 seconds
Explanation:
Earth's moon is the brightest object in our
night sky and the closest celestial body. Its
presence and proximity play a huge role in
making life possible here on Earth. The moon's gravitational pull stabilizes Earth's wobble on its axis, leading to a stable climate.
The moon's orbit around Earth is elliptical. At perigee — its closest approach — the moon comes as close as 225,623 miles (363,104 kilometers). At apogee — the farthest away it gets — the moon is 252,088 miles (405,696
km) from Earth. On average, the distance fromEarth to the moon is about 238,855 miles (384,400 km). According to NASA , "That means 30 Earth-sized planets could fit in between Earth and the moon."
Explanation:
sinces : Momentum = velocity × mass
then : 30 = 10 × m and m = 30 ÷ 10 = 3 kg