Physics

4. prevention of wasteful use of a resource
5. the moving of something from its place or position
9. the force that attracts a body toward the centre of the earth, or toward any other physical body having mass
10. a state in which opposing forces or influences are balanced
15. the strength and vitality required for sustained physical or mental activity
16. relating to or resulting from motion
18. occurring or produced as a result or consequence of something

1. the speed of something in a given direction
2. strength or energy as an attribute of physical action or movement
3. increase in the rate or speed of something
6. a tendency to do nothing or to remain unchanged
7. the state or quality of being efficient
8. the rate at which someone or something is able to move or operate
11. a coherent, typically large body of matter with no definite shape
12. an inclined part of a road or railway; a slope
13. a body's relative mass or the quantity of matter contained by it, giving rise to a downward force; the heaviness of a person or thing
14. having or showing the capacity to become or develop into something in the future
17. an amount of space between two things or people