Physics Unit 3

2. a force past each other of objects that are touching; examples include rough surfaces and air resistance
5. a force acting on an object or system that originates outside of the object or system
9. the vector sum of all external forces acting on an object or system; causes a mass to accelerate
10. defined by the boundaries of an object or collection of objects being observed; all forces originating from outside of the system are considered external forces.
13. the pulling force that acts along a medium, especially a stretched flexible connector, such as a rope or cable; when a rope supports the weight of an object, the force on the object due to the rope is called a tension force.

1. a push or pull on an object with a specific magnitude and direction; can be represented by vectors; can be expressed as a multiple of a standard force
2. a sketch showing all of the external forces acting on an object or system; the system is represented by a dot, and the forces are represented by vectors extending outward from the dot
3. the tendency of an object to remain at rest or remain in motion
4. a body at rest remains at rest, or, if in motion, remains in motion at a constant velocity unless acted on by a net external force; also known as the law of inertia
6. the force that a surface applies to an object to support the weight of the object; acts perpendicular to the surface on which the object rests
7. for every action there is an equal, but opposite reaction
8. when an external unbalanced force acts on an object, that object will accelerate
11. the quantity of matter in a substance; measured in kilograms
12. the force due to gravity acting on an object of mass m; defined mathematically as: Fg=mg, where g is the magnitude and direction of the acceleration due to gravity