Physical Science 2Q sem

Week #1

QUARTER 2

500BC

  • Most ancient Greeks believed that Earth was round, not flat

  • Pythagoras said that the Earth is → Spherical → aesthetics (perfect shape)

384-322BC

  • Aristotle second the motion that the Earth is → Spherical → Physical evidence

    • Ships disappear over the horizon

    • Earth round shadow during lunar eclipse

    • Different constellations visible at different latitudes

The Earth spins at 1600 km/h

Geocentric

Heliocentric

  • Copernicus

  • Earth is not the center of the universe

  • Earth is

Week #

Newtonian Mechanics

  • Fundamental quantities - distance (m), time (s), mass (kg) are absolute.

  • Objects move in a straight line

  • There is no change in time where you are or how fast you are moving.

  • All speeds are relative - it depends on the observers, viewpoint, and shadow.

Maxwell’s Electromagnetic Theory

  • Light has electrical and magnetic components with same direction but different orientation.

  • Light moves at a constant speed of 300,000 km/s

  • Speed of light is the same for all observers

  • Speed of light does not change for all observers and situations

Limitations

Newtons Mechanics

  • Absolute Time and Space: Time flows uniformly for all observers, and space is the same everywhere.

  • Instantaneous Effects: Forces, like gravity, act instantaneously over any distance

Maxwell’s Theory

  • A Luminiferous Ether: Light waves,

Resolution to Newton’s and Maxwell’s ideas special theory of relativity

2 postulates:

  • All the laws of physics remain the same in all inertial frames.

  • The speed of light is the same value in a vacuum, c = 300,000,000 m/s (3.0 × 10^8 m/s), in all inertial frames, regardless of velocity of the observer or the velocity of the source emitting the light.

Inertial Frame Reference

  • It depends on how you view or observe the world.

General Theory of Relativity

2 postulates:

  • All the laws of nature have the same form for observers in any frame of reference, accelerated or not

  • In the vicinity of any given point, a gravitational field is equivalent to an accelerated frame of reference without a gravitational field (field of equivalence).