Forces and Newton's Laws

2. The un balanced force acting on an object equals the object’s mass times its acceleration.
9. force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. ..
10. An object's speeding up toward the center of the earth (or any planet) due to its gravity.
13. Sum of all the forces acting on a body.
14. The force of friction that exists between a stationary object and the surface on which it's resting.
16. Forces acting on an object that combine to produce a net for e equal to zero.
18. friction of force applied by the air on bodies that are moving through it.
20. The motion of a body when only the force of gravity is acting on it.

1. forces acting on an object that combine to produce a net nonzero force which may cause motion.
3. the resistance created by two objects sliding against each other.
4. Velocity of a falling object when the gravity and air resistance becomes equal.
5. The attraction between two particles of matter due to their mass.
6. friction that occurs when a wheel, ball, or cylinder rolls freely over a surface, as in ball and roller bearings. T
7. Amount of matter in a substance.
8. For every action force there is an equal and opposite reaction force.
11. The force between two objects in contact that opposes the motion of either object.
12. An object at rest remains at rest and an object in motion maintains its velocity unless it experiences an unbalanced force.
15. The SI unit for force.
17. The tendency of an object to remain at rest of in motion with a constant velocity until an external force acts upon it.
19. Effect of gravity on the mass of an object.