Topic 3 Galileo: Return to Earth
Aristotle BC
Four Elements Earth Water Air Fire Aether
Natural Motion: Elements tend to seek their natural place. Violent Motion: Any forced motion that opposes natural motion. (Push or Pull) The speed of a moving object is directly proportional to the force moving it.
Aristotle’s Laws of Motion 1.Rest is the natural state of an object. 2. Heavier things fall faster, the speed proportional to the weight.
Some definitions: Displacement= distance the object covers and the direction it came from… Velocity= change in displacement in time (note: it is speed AND direction) Speed is only how fast the object moves Acceleration= change in velocity in time.
Galileo Galilei ( )
Two New Sciences
Aristotle’s fall
Galileo’s fall
A thought experiment GIVEN: three identical weights dropped from the same height
Does a ten pound weight fall ten times faster than a one pound weight?
Can Galileo measure free fall?
Dilute the process
Galileo observed D 1 = 1 D 1 D 2 = 3 D 1 D 3 = 5 D 1 D 4 = 7 D 1
Galileo observed
Note increasing Velocity
Does it really work? Distance time (time) 2 d/t d/t
Our results
2 ramps?
Rest was not a natural state. The concept of inertia was introduced.