The three parts of the Earth are Atmosphere, Hydrosphere and Lithosphere.
Atmosphere is the blanket of air that surrounds the earth. It is densest close to the surface and thins out as one moves higher. Atmosphere of Earth contains mainly Nitrogen, followed by Oxygen and small amounts of water vapor, Carbondioxide and other gases.
Lithosphere is the outer most part of the earth's surface. The Earth's crust and the mantle form Lithosphere.
Hydrosphere is the part of the Earth that has water. The Oceans, seas, rivers, lakes and other water bodies constitute the Hydrosphere.
Stratosphere, Mesosphere and Ionosphere are different layers of atmosphere.
Hence, for the study of the Earth, one needs to consider earth to be made of three parts- atmosphere, Lithosphere and Hydrosphere.
A 'velocity' is built out of a speed and a direction.
The only item on that list that has a speed and a direction is the <em>first one</em>. The speed is 30 m/s and the direction is south.
Answer:
4.53482 m/s
4.506 m/s
Explanation:
= Mass of player = 75 kg
= Initial velocity of player = 4.6 m/s
= Mass of ball = 0.47 kg
= Initial velocity of ball = 15 m/s
The linear momentum of the system is conserved

The player's speed is 4.53482 m/s
In the second case the equation of momentum is

The player's speed is 4.506 m/s