- Per-Second-per-Second-I.mp3
- Per-Second-per-Second-I.mp4
- Per-Second-per-Second-II.mp3
- Per-Second-per-Second-II.mp4
- Per-Second-per-Second-intro.mp3
[Intro]
Thirty-two feet
(Per second per second)
Oh, that’s deep
(Square aware)
[Verse 1]
Which falls faster
An egg or a rock
Why at the same clock
Though the egg’s a disaster
[Chorus]
Thirty-two feet
(Per second per second)
Oh, that’s deep
(Square aware)
[Bridge]
Falling (falling fast)
Falling faster (as time goes past)
32, 64, 128
(An exponential rate)
[Verse 2]
Now I’ve come to know
How fast things go
There for a second…
I had to reckon
[Chorus]
Thirty-two feet
(Per second per second)
Oh, that’s deep
(Square aware)
[Bridge]
Falling (falling fast)
Falling faster (as time goes past)
32, 64, 128
(An exponential rate)
[Chorus]
Thirty-two feet
(Per second per second)
Oh, that’s deep
(Square aware)
[Outro]
I’m aware
(Squared there)
A SCIENCE NOTE
What Does “Per Second Per Second” Mean?
- “Per second per second” refers to acceleration, the rate at which velocity changes over time. For example:
- If an object’s velocity increases by 10 m/s1 every second, it has an acceleration of 10 m/s2.
- This is read as “meters per second squared” or “meters per second per second.”
How Fast Does an Object Fall?
- Near the surface of the Earth, objects fall with an acceleration due to gravity, denoted by gg, approximately 9.8 m/s2 (or 32 ft/s2 — 32 feet per second per second).
- Assuming no air resistance, the speed of a falling object can be calculated using the formula:v=g⋅t
where:- v is the velocity,
- g=9.8 m/s2
- t is the time in seconds.
Example:
- After 1 second: v=9.8 m/s v = 9.8.
- After 2 seconds: v=19.6 m/s v = 19.6.
- After 3 seconds: v=29.4 m/s v = 29.4
Do Objects Fall at the Same Speed Regardless of Weight?
- In the absence of air resistance (in a vacuum), all objects fall at the same rate regardless of their mass. This is because the force of gravity acts equally on all objects relative to their mass.
- Example: A feather and a hammer will fall at the same rate in a vacuum (as demonstrated during the Apollo 15 moon landing).
- With air resistance, heavier or denser objects usually fall faster because they are less affected by drag. For example:
- A bowling ball falls faster than a feather in Earth’s atmosphere due to the feather’s higher air resistance relative to its weight.
Key Equations and Concepts
- Distance Fallen Over Time:d=1/2 gt2 .
- Terminal Velocity:
- In real-world conditions, objects reach a maximum falling speed (terminal velocity) when air resistance balances the force of gravity. This is why rain does not kill you.
- Galileo’s Discovery:
- Galileo showed that objects fall at the same rate regardless of their weight, overturning Aristotle’s earlier belief that heavier objects fall faster.