Monday, June 26, 2023
Sunday, June 25, 2023
Saturday, June 24, 2023
Dropping a Rock Down an Abandoned Coal Mine Shaft
3 weeks ago
Here's some math for you
The equation for the distance traveled of a free falling object is:
h = v_0t + 1/2(gt^2)
h equals height in meters;
v_0t equals initial velocity in meters per second;
g equals acceleration due to gravity in meters per second squared;
t equals time in seconds.
The initial velocity is 0 since the rock was being held at a standstill by the man. Simplifying the equation we get:
h = 1/2(gt^2)
I watched the video several times and came up with an approximate free fall time of 7.35 seconds. We know that acceleration due to gravity is 9.8 m/s^2. Plugging in the numbers we get:
h = 1/2(9.8 x 7.35^2)
Solving for h we come up with:
h = 264.71 meters
The rock fell approximately 264.71 meters, or about 868.47 feet.
Now that we have a number for distance, we can now see how much the speed of sound affects the equation.
Speed of sound is 343 meters per second
264.71 / 343 = 0.77175
The sound of the rock hitting the bottom was delayed by about 0.77 seconds, which means we need to subtract that time from the original 7.35 seconds.
7.35 - 0.77 = 6.58 seconds of free fall.
Now we have a new free fall time, and can solve for h again with the new number:
h = 1/2(gt^2)
h = 1/2(9.8 x 6.58^2)
h = 212.15
So the rock actually fell about 212.15 meters, or 696.03 feet.
Air resistance would play a role as well, so it may be more like 200 meters or 650 feet, but Ima stop there.
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Monday, June 19, 2023
Sunday, June 18, 2023
Saturday, June 17, 2023
Why aliens haven't visited Earth
Kim Komando: "I know why aliens haven't visited Earth. We only have a one-star rating."
In the fictional "Hitchhiker's Guide to the Galaxy", the listing for Earth only says, "Mostly harmless."
Friday, June 16, 2023
Thursday, June 15, 2023
Monday, June 12, 2023
Friday, June 9, 2023
Wednesday, June 7, 2023
Tuesday, June 6, 2023
Sunday, June 4, 2023
Saturday, June 3, 2023
Snake eating itself
https://youtu.be/puKevC5boFg
Perhaps a Darwin Award for a snake.
Maybe hand sanitizer would be a snake repellent.
Best wishes,
John Coffey
Perhaps a Darwin Award for a snake.
Maybe hand sanitizer would be a snake repellent.
Best wishes,
John Coffey
Friday, June 2, 2023
Chemo is Weird, Y'all
Been watching this YouTuber, Hank Green, for about 13 years. (The first video I saw is this one: https://www.youtube.com/watch?v=yRRGaxx8Zf4)
A couple of weeks ago he announced that he had lymphoma: https://www.youtube.com/watch?v=x6a4hMyiwBo
He alternates making youtube videos with his brother John, who wrote the book, "The Fault in Our Stars" which was made into a terrific movie. John Green appears in a deleted scene of the movie: https://www.youtube.com/watch?v=PEEQ6-4nKYQ
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