BIO Weighing a Virus. In February 2004, scientists at Purdue University used a highly sensitive technique to measure the mass of a vaccinia virus (the kind used in smallpox vaccine). The procedure involved measuring the frequency of oscillation of a tiny sliver of silicon (just 30 nm long) with a laser, first without the virus and then after the virus had attached itself to the silicon. The difference in mass caused a change in the frequency. We can model such a process as a mass on a spring. (a) Show that the ratio of the frequency with the virus attached (fS + V) to the frequency without the virus (ƒS) is given by where mV is the mass of the virus and mS is the mass of the silicon sliver. Notice that it is not necessary to know or measure the force constant of the spring. (b) In some data, the silicon sliver has a mass of 2.10 X 10-15 g and a frequency of 2.00 X 1015 Hz without the virus and 2.87 X 1014 Hz with the virus. What is the mass of the virus, in grams and in femtograms?
MCOM 151 – Weekly Task List Assignments due @11:59pm of due date Week Assignment Due Date Grade Week 1 ▯ Read Chapter 1 Jan. 9- ▯ Watch Chapter 1 Online Lecture Jan. 15 January 11, /10 ▯ Quiz Chapter 1 2017 /10 ▯ Complete “My Name Is…” Discussion January 11, /20 ▯ Complete Weekly Discussion (min. 2017 January 11, 2 req.) 2017 ▯