Newton's First Law and Free Body Diagrams

Issac Newton

- 1642-1727
-Universal Law of Gravitation
-Classical Mechanics

Aristotle

-4th century BC
-Motion-natural v. violent

natural motion

objects seek their natural resting places

violent motion

imposed motion resulting from an external push or pull

Copernicus

-1473-1543
-Astronomer
-Earth moves around Sun (controversial)

Galileo

-1564-1642
-Dropped things off the Leaning Tower of Pisa
-Huge influence on Newton
-Died when Newton was born

inertia

the tendency of an object to resist a change in motion

mass

matter in an object, directly related to inertia, the more mass, the more inertia

newton's first law

an object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force

inclined planes

Ramp: ball increased speed down, decreases rolling up
Flat: has constant speed (no acceleration)
Valley: rolled down, came shy of where it was dropped

balanced force

object will not have a change in motion

unbalanced

will have a change in motion

friction force

-the force exerted by a surface as an object moves across it or makes an effort to move across it
-moves against object's motion
-static-keeps objects at rest
-sliding-2 objects rubbing
-rolling-rolls across surface
-fluid-object moving through fluid

applied force

a force which is applied to an object by a person or another object

normal force

the support force exerted upon an object that is in contact with another stable object

tension force

the force that is transmitted through a string, rope, cable or wire when it is pulled tight by forces acting from opposite ends

gravity force

the force with which the earth, moon, or other massive body attracts an object towards itself (-9.8 = Earth)

air resistance force

-force that acts upon objects as they travel through the air
-frictional force in air
-greater the surface area, more air resistance

acceleration

change in velocity over a period of time (speed up, slow down, change in direction)