AP Physics: Forces

Force

a push or pull, vector quantity (direction matters), units: Newtons (N)

Net force

sum of all the forces acting on an object (2 types)

Balanced Net force

forces exactly cancel each other out, ex: tug-o-war stalemate, net force=0

Unbalanced Net force

forces do not cancel each other out, ex: tug-o-war has a winner, net force does not = zero

Contact force

forces that act with direct contact (wind, slap, push, pull)

Field Force

forces that act at a distance, without direct contact (gravity, magnet)

Friction

force exerted by a surface as an object moves across it (or makes an effort to move across it, always opposes motion or attempted motion, symbol=F_Fr

Normal Force

Support force perpendicular to the surface an object is in contact with, symbol=F_N

Air Resistance

friction that acts on an object moving through the air, opposes motion, F_Air

Other Contact Forces

Applied force F_App, F_Push;F_Pull, F_Car, if by a rope F_T (F_Tension)

Force of Gravity

another name for weight, the force with which the moon, earth, or another massive body attracts an object toward itself, F_G=symbol, equation F_G=mass x gravity, on earth it equals 9.8 or 10

Mass

amount of matter an object has, unit: kg, doesn't change anywhere in the universe

Weight

force of gravity acting upon an object, unit: N, depends on amount of gravity experiencing, AKA force of gravity

center of mass

average position of an object/system’s mass

Free body diagrams

shows the outside forces acting on an object

Dot

can be one object or multiple objects/system, center of mass of that object/system

freefall

only force acting on it is the force of gravity

Newton’s 1st Law of Motion

AKA the law of inertia, an object at rest will remain at rest, an object in motion will remain in motion (at constant velocity & in same direction), unless acted upon by an outside force

Inertia

the tendency of an object to maintain it state of motion, resist acceleration, more mass object has more inertia it has

equilibrium

occurs when objects are at rest OR when objects are moving at a constant velocity (No Acceleration), when in this objects are balanced (net force=0)

Σ (sigma)

the sum of

F_N≠F_G

When object is pulled at an angle or pushed down at an angle…..

Break into components

If a force is at an angle……