This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: oldhomewk 02 YOO, HEE Due: Jan 17 2008, 4:00 am 1 Question 1, chap 1, sect 99. part 1 of 1 10 points Assume the Sun is mostly composed of hy drogen atoms. Assume the mass of the Sun is 1 . 6 10 30 kg, and the mass of a hydrogen atom is 1 . 672 10 27 kg. How many atoms are there in the Sun? Correct answer: 9 . 56938 10 56 atoms (toler ance 1 %). Explanation: Basic Concepts: Elementary Arithmetic N atoms = M sun M atom = 1 . 6 10 30 kg 1 . 672 10 27 kg = 9 . 56938 10 56 atoms . Question 2, chap 1, sect 99. part 1 of 1 10 points Assuming 83 . 9 heartbeats / min, estimate the total number of times the heart of a hu man beats in an average lifetime of 97 years. Correct answer: 4 . 28049 10 9 heartbeats (tolerance 5 %). Explanation: The heart rate must be multiplied by the lifetime, with proper conversions heartbeats min min year years heartbeats A conversion factor for min year can be easily derived (60 min / h) (24 h / day) (365 . 256 day / year) = 525969 min / year lifetime heartbeats = (83 . 9 heartbeats / min) (525969 min / year) (97 years) = 4 . 28049 10 9 heartbeats . Question 3, chap 1, sect 99. part 1 of 1 10 points Assume: The diameter of the tire is 2 . 5 ft . An automobile tire is rated to last for 40000 mi. Estimate the number of revolutions the tire will make in its lifetime. Correct answer: 2 . 68908 10 7 rev (tolerance 1 %). Explanation: The diameter of a tire is 2 . 5 ft, with a circumference of C = d . Thus the tire would make (40000 mi) 5280 ft 1 mi 1 rev (2 . 5 ft) = 2 . 68908 10 7 rev . Question 4, chap 1, sect 6. part 1 of 1 10 points A fisherman catches two sturgeons. The smaller of the two has a measured length of 94.27 cm (two decimal places and four signif icant figures), and the larger fish has a mea sured length of 148.8 cm (one decimal placesured length of 148....
View Full
Document
 Spring '08
 Turner
 Mass

Click to edit the document details