In another experiment, you place a layer of this cryoprotectant between one 10 cm * 10 cm cold plate maintained at -40C and a second cold plate of the same size maintained at liquid nitrogens boiling temperature (77 K). Then you measure the rate of heat transfer. Another lab wants to repeat the experiment but uses cold plates that are 20 cm * 20 cm, with one at -40C and the other at 77 K. How thick does the layer of cryoprotectant have to be so that the rate of heat transfer by conduction is the same as that when you use the smaller plates? (a) One-quarter the thickness; (b) half the thickness; (c) twice the thickness; (d) four times the thickness.
Chapter 2: Simple Harmonic Motion 2.1 The Simplest Vibration 1. What is the simplest possible system that demonstrates vibration a. A mass suspended on a spring demonstrates our system at rest: the mass is at the equilibrium position, and the spring is (somehow) stretched, also in it equilibrium position. i. The force of gravity balances the elastic force from a spring. ii. This elastic force depends on the elongation of our spring: 1. F = kx a. x is elongation and k is stiffness b. k depends on thickness of the wire as well as on the material our spring is made of. c. The minus sign demonstrates that elastic force is always directed against elongation (squeezing), trying to bring the suspended mass back to the equilibrium point. i. This kind of force is called restoring force, and its presences is necessary
