swansont

The period depends on sqrt (l/g) So, as YT said, the distance to the bob, which can depend on environmental factors such as temperature, as well as the accceleration due to gravity. All else being equal, a pendulum swings more slowly on the top of a mountain, or even when the moon is overhead.

Onion skin, perhaps, or something similar.

He posted that 2 years ago, so I'd cut him a little slack.

If it keeps glowing after long periods without any light to charge it up, it's radioactive. That means the phosphor is being charged up by a decay.

I just got one, but reclicking on the link then worked OK.

Any glow-in-the-dark paint you can acquire these days is not likely to be radioactive.

How can something be "very unique?"

"This web site is intended as a time-of-day service only. It should not be used to measure frequency or time interval, nor should it be used to establish traceability to NIST or the USNO." "REAL time" is a bit of a misnomer. It all depends on how well you can realize the definition of the second, and transmit that information. Over the internet, that's limited to about a millisecond with NTP (Network Time Protocol) Anyway, the two sources in the US, as the site says, agree to better than a microsecond. But the USNO follows the BIPM (the International standard) a little more closely. But then, we contribute upwards of half of the data that they collect. edit to add: and I always chuckle at the mention of "the" atomic clock. The time that gets disseminated from USNO is the averaging of dozens of atomic clocks.

The Secret Service pounced on the pretzel and wrestled it to the ground before that could happen.

You lose causality. Effect can precede the cause, in some frame of reference. Which is a contradiction. It's not "just because" relativity says it - relativity has been tested, so we are pretty confident that it's right.

This is worded a tad awkwardly. The acceleration to large speeds gives the particles the energy. It isn't produced in the collision.

The kicker with the larger planets is that I think it's the large gravitational forces that tear the moons apart and/or keep them from forming in the first place. Obviously with the Earth that's not happening. I'm not sure how much the moon sizes matter. It's possible that if the moon were destroyed, but the mass were kept in orbit, that it might gravitationally re-coelesce to some extent.

The gravitational force varies as the inverse-square of r.

grade 12 where? Curricula vary from country to country (and in the US, probably from state to state) And what one person means by grade 12 might be different as well. When I was in 12th grade, I was taking calculus. Is that what you want?

Output/input > 1

But...but...but...they use them on STAR TREK!

I thought Time was a magazine...