This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: chauhan (mmc2762) – Ch4H2 – turner – (56910) 1 This printout should have 12 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 10.0 points If a chain of 30 identical short springs linked end to end has a stiffness of 240 N / m, what is the stiffness of one short spring? Correct answer: 7200 N / m. Explanation: Springs in series have the effective stiffness K , where K is given in terms of the stiffnesses of the individual springs as follows: 1 /K = 1 /k 1 + 1 /k 2 + · · · + 1 /k N . For identical springs, we have k = NK , where k is the stiffness of a single spring. Therefore k = (30)(240 N / m) = 7200 N / m . 002 10.0 points You place 40 identical springs side by side (in parallel) and connect them to a large, massive block. The stiffness of the 40spring combi nation is 20025 N / m. What is the stiffness of one of the individual springs? Correct answer: 500 . 625 N / m. Explanation: Springs in parallel have an effective stiffness K , where K is given in terms of the stiffnesses of the individual springs as follows: K = k 1 + k 2 + · · · + k N . For identical springs, we have K = Nk , or k = K/N , where k is the stiffness of a single spring. Therefore, k = 20025 N / m 40 = 500 . 625 N / m . 003 (part 1 of 4) 10.0 points One mole of tungsten (6 . 02 × 10 23 atoms) has a mass of 184 g, and its density is 19 . 3 g / cm 3 , so the centertocenter distance between atoms is 2 . 51 × 10 10 m. You have a long, thin bar of tungsten, 2 . 8 m long, with a square cross section, 0 . 1 cm on a side. You hang the rod vertically and attach a 420 kg mass to the bottom, and you observe that the bar becomes 1 . 24 cm longer. From these measurements, it is possible to determine the stiffness of one interatomic bond in tungsten....
View
Full
Document
 Spring '11
 Antoniewicz
 Physics, Atom, Mole, Correct Answer, rod, Chauhan

Click to edit the document details