The document discusses the history and key concepts of motion. It describes Aristotle's view that terrestrial motion involves objects returning to their natural place on Earth, while celestial motion involves uniform circular orbits. It also outlines Newton's laws of motion, Kepler's laws of planetary motion including elliptical orbits and equal areas over time, and how Tycho Brahe's observations enabled Kepler's laws. Hipparchus and Copernicus contributed by explaining the precession of equinoxes and describing Earth's diurnal and annual motion around the Sun.

1. MOTION

2. OBJECTIVES
• Characterize Motion
• Explain the contribution of The Greeks in the study of motionand Earth
• Differentiate diurnal motion, annual motion, and precision of the
equinoxes
• Explain how Brahe’s innovation and extensive collection of data in
observational Astronomy paved the way for Kepler’s law of planetary
motion; and
• Apply Kepler’s Third law of planetary motion to objects in the solar
system

3. OBSERVING MOTION
In July 1969, Neil Armstrong(1930-2012), an American
astronaut have touched and walked on the Moon.
Armstrong was able to leap at the surface of the Moon at a
height, which he could have not reached on Earth because of
gravity. As you know, the gravitational force of Moon is less
compared to that on Earth.

4. IF THERE’S SOMETHING
PERFECTLY STILL, WITH NO
MOVEMENT AT ALL, CAN YOU
SAY THAT IT’S IN MOTION?

5. REFERENCE POINTS
• A place or object used for comparison to examine if something is in motion. An
object is in motion if it changes position relative to a reference point.
• Example:

6. ARISTOTLE’S VIEW OF MOTION
• For Aristotle, motion did not only refer to
locomotion or a change in postion. He
classified motion as terrestrial (sublunar)
and celestial.
• Terrestrial motion is the movement of
objects on Earth.
• According to Aristotle, the Earth is the
center of the universe and it is made up
of four elment: earth(center), water, fire
and air.
• When an element is removed from its
natural place , it would return to its
natural place following a straight
line(retilinear) motion.
Example:
This example illustrates a type of
terrestrial motion called natural
motion.
Another type of terrestrial motion is
violent motion (unnatural motion).

7. CELESTIAL MOTION
• The motion of celestial bodies which only possessed the tendency for uniform
circular motion.
• Example:

8. NEWTON’S LAW OF MOTION
PRINCIPIA MATHEMATICA PHILOSOPHAE NATURALIS,1686
“An object in motion will remain in motion, and an object at rest will
remain at rest, unless acted upon by a force.”
“Net force is equal to mass times acceleration”
“For every action there’s an equal but opposite reaction.”
“Everybody persists in its state of being at rest or of moving uniformly
straight forward except insofar as it is compelled to change its state by
force impressed.”l
“To every action there is always an equal and opposite reacton or the
forces of two bodies on each other are always equal and are directed in
opposite directions.
1st Law
2nd Law
3rd Law

9. HIPPARCHUS’ VIEW OF MOTION
• Hipparchus of Nicaea(190 BCE – 120 BCE) was
able to determine perfectly the circumference
of the Earth. Once considered the greatest
observational astronomer because he
explained the precession of equinoxes (refers
to the movement of Earth relative to it’s
orbital plane). This phenomenon accounts for
the seemingly continuous displacement of
stars relative to the equinoxes(An equinox is
commonly regarded as the moment when the
plane of Earth's equator passes through the
center of the Sun's disk, which occurs twice
each year, around 20 March and 23
September).

10. COPERNICUS’ VIEW OF MOTION
• Two description of Earth’s motion:
• 1. Diurnal Motion refers to the
rotation of the Earth about its axis
from East to West
• -results to the occurrence of
day and night
• - a day is required for one
cycle for diurnal motion

11. ANNUAL MOTION
• Movement of Earth in reference to the
sun.
• Two types of annual motion:
• Revolution And Tiltation
• This takes
• Around 365 ¼ (365 days and 6 hours),
reference for the number of days in a
standard year.
• The occurrence of seasons(Spring,
Summer, Autummn, and Winter) is a
consequence of both Earth’s
revolution and tilted axis.

12. BRAHE’S
CONTRIBUTIONIN
OBSERVATIONAL
ASTRONOMY
• Rudolphine Table –
records of celestial
observation he made using
his crude astronomical
Instruments.

13. RUDOLPHINE TABLE
(TABULAE RUDOLPHINAE)
• Published by Johannes Kepler in
1627 using some observational data
collected by Tycho Brahe (1546-
1601)
• Rudolphine in memory of Rudolf II,
Holy Roman Emperor
• Kepler is the successor of Brahe
since he died on 1601, one year
after Kepler joined working on the
tables
• Consists of star catalogue and
planetary tables

14. KEPLER’S LAW OF PLANETARY
MOTION
• Kepler’s was a German
Mathematician and astronomer
became fous for his laws : laws of
planetary motion, the law of
ellipses, Law of equal areas and
law of harmonies.
• Law of Ellipses refers to the
Elliptical path of the planets with
the sun at one focus. Aphelion(
farthest Earth orbit point from the
sun) and Perihelion(nearest Earth
orbit point from the sun).

15. LAW OF EQUAL AREAS
• As a planet moves at any point
along its elliptical orbit, it
travels equal areas of space at
equal periods of time.

16. LAW OF HARMONIES
• The squares of the revolutions of the planets are directly proportional to the cubes
of their average distances from the sun. This is expressed as
•
𝑇 𝐴
2
𝑇 𝐵
2 =
𝑟 𝐴
3
𝑟 𝐵
3
• 𝑇𝐴 - the revolutionary period of planet A
• 𝑇𝐵 - the revolutionary period of planet B
• 𝑟𝐴 - the average distance of planet A from the sun
• 𝑟𝐵 - the average distance of planet B from the sun

17. NOW LET’S THIS LAW IN SOLVING
PROBLEMS
Example: Mars and Jupiter are plants in the solar
system orbiting the Sun. Using the Law of
Harmonies, compute the average distance of the
Jupiter from the sun given that Mars is 1.524
astronomical units away from the sun and moves
around the sun 1.88 earth years. Jupiter moves
around the Sun in 11.86 earth years.

18. REVIEW
• Reference Point
• Aristotle’s View of Motion
Terrestrial Motion
Celestial Motion
. Newton’s Law of Motion
. Hipparchus’s View of Motion
. Copernicus’s View of Motion
Diurnal Motion
Annual Motion
.
Brahe’s Contribution
. Kepler’s Law of
Planetary Motion
Law of Ellipses
Law of Equal Areas
Law of Harmonies