Earth Spheres. Earth's Spheres. Everything in Earth's system can be placed into one of four major subsystems: land, water, living things, or air. These four subsystems are called “spheres.” Specifically, they are the lithosphere (land), hydrosphere (water), biosphere (living things), and atmosphere (air).
Answer:


Explanation:
The statement is described physically by means of the Principle of Momentum Conservation. Let assume that first person moves in the positive direction:
First Person

Second Person

The final velocities of the two people after the snowball is exchanged is:


F = m*a, mass times acceleration.
F = 15*10 = 150 N
Answer:
(i)
, (ii)
, (iii) 
Explanation:
(i)
and
represent the points where particle has a velocity of zero and spring reach maximum deformation, Given the absence of non-conservative force and by the Principle of Energy Conservation, the position where particle is at maximum speed is average of both extreme positions:

(ii) Maximum accelerations is reached at
and
.

(iii) Greatest net forces exerted on the particle are reached at
and
.
