physics

5. 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.
8. the length of the space between two points.
9. the rate at which an object's position changes, measured in meters per second
11. a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.
12. the ratio of the useful output energy or power of a system to its total input energy or power.
14. an increase or decrease in the magnitude of a property (e.g. temperature, pressure, or concentration) observed in passing from one point or moment to another.
15. a state where an object's motion (both linear and rotational) remains constant over time
16. the net effect of multiple forces acting on an object, represented as a single force.
17. the speed of something in a given direction.
18. the potential energy per unit of some quantity due to a field.

1. a vehicle's capacity to gain speed.
2. strength or energy as an attribute of physical action or movement.
3. a form of energy that an object or a particle has by reason of its motion
4. the action of moving something from its place or position.
6. the force that attracts a body towards the centre of the earth, or towards any other physical body having mass.
7. a large body of matter with no definite shape.
10. the capacity to do work
13. something which doesn't change