A 10.0-g marble is gently placed on a horizontal tabletop that is 1.75 m wide. (a) What is the maximum uncertainty in the horizontal position of the marble? (b) According to the Heisenberg uncertainty principle, what is the minimum uncertainty in the horizontal velocity of the marble? (c) In light of your answer to part (b), what is the longest time the marble could remain on the table? Compare this time to the age of the universe, which is approximately 14 billion years. (Hint: Can you know that the horizontal velocity of the marble is exactly zero?)
ASTRO Lesson 6 – the moon Lecture 31, 32 ▯ ▯ Escape speed of the moon is about 1/6 of the earth For earth = 11.2 km/s For moon = 2.4 km/s ▯ ▯ Earth doesn’t rotate around sun, center of mass of the earth-moon system rotates around the sun ▯ ▯ Sister theory Moon and earth formed at about the same time, with the same stuff and became the way they are now Chemical compositions of dirt on the moon and earth are pretty similar - surfaces Density of the moon is way less than the density of the earth Not great ▯ Daughter theory When earth first formed, it was a giant molten ball of stuff (spinning fast). A chunk of the earth smashed off and created the moon
