| Physics for the Inquiring Mind [Phys 105] Fall 2003 |
[1] You have a board of five mounted coils of wire in your kit. The five pieces of wire are labeled (1) 10 meters of 22 gauge Copper wire, (2) 10 meters of 28 gauge Copper wire, (3) 20 meters of 22 gauge Copper wire, (4) 20 meters of 28 gauge Copper wire, and (5) 10 meters of 22 gauge Copper-Nickel wire.
By using the circuit below and varying which of the five coils of wire you use in your circuit, rank your five coils from lowest resistance to highest resistance.
What do your results imply about the effect of the length of a piece of wire on its resistance? What do they imply about the effect of the gauge of a piece of wire on its resistance?
[2] Complete Experiment 4.8 on p. 413.
[3] There is a green box marked P64012 in your kit. Open it and carefully remove the assembly inside. Use the red and black wires coming off of the assembly to attach it to your battery pack. See if you can get the armature to spin.
After you have gotten your armature to spin, try to figure out why it is spinning! Explain as clearly as you can why it is spinning, and describe the function of each of the components of your motor [your assembly is a very simple example of what is called a DC motor].
[4] As homework for Thursday, October 23, do Experiment 4.6 on p. 411 [just the question part; you needn't set anything up], Exercise 4.9 on p. 413, Exercise 4.10 on p. 414, and Exercise 4.11 on p. 415.