1. A Brief History in Physics
Honors Physics - Introduction to Free Fall

2. What Makes Things Move?
“Impetus”
Aristotle
384 – 322 B.C.

3. Why Do Objects In Motion Slow Down?
“They get tired.”
Aristotle
384 – 322 B.C.

4. Why Do Objects Move Toward the Earth?
“Objects yearn to be reunited with the earth.”
Aristotle
384 – 322 B.C.

5. Why do objects actually fall?

6. The birth of modern physics
Galileo Galilei
1564 – 1642
Astronomer
Physicist
Mathematician
Philosopher
Engineer
Many many contributions

7. Many contributions.. Inertia Kinematics Thermoscope
Law of falling bodies
Improved the telescope
Simple harmonic motion
Parabolic trajectory of projectiles
Publicly supported heliocentric system
Enforced the scientific method by testing hypothesis via experiment

8. How does a ball fall downward?
Does position increase, decrease, or remain constant?
Does velocity increase, decrease, or remain constant?
Does acceleration increase, decrease, or remain constant?

9. How can we measure it?
Piza

10. Gravitational field “Acceleration due to gravity” Denoted as “g”
Uniform acceleration directed toward the center of the Earth
g = 9.81m/s2
+ or – depending on how you analyze the problem
Letting upward represent the + direction and downward represent the – direction is a bit more conventional

11. Do heavier objects fall faster?
Compound body thought experiment

12. Why don’t objects speed up indefinitely?

13. Measuring freefall
Pisa

14. Apollo 15 Commander David R. Scott August 2nd, 1971 Hammer vs. feather
Absence of air resistance (in a vacuum)
watch?v=5C5_dOEyAfk

15. So how fast can objects fall?
Felix Baumgartner, Oct 14, 2012
39,068.5 meters / 128,177.5 feet / Mach 1.25

17. Let’s Physics
The speed of sound is m/s. How long did it take Felix to break the sound barrier and how far did he fall?
Note: Use g = 9.81m/s2
“g” actually varies as he falls..
Time elapsed = 34.9s
Displacement= -5902m