A student calibrates an unmarked liquid-in-glass thermometer. He places the thermometer bulb in ice at 0°C and marks the position of the end of the
liquid thread.
He then places the thermometer bulb in steam at 100°C and marks the position of the
end of the liquid thread.
(a) Explain why the student places the thermometer bulb in melting ice and in steam.
(1)
(b) Fig. 1.1 shows the thermometer next to a ruler.
Line A is the mark made when the thermometer bulb is in the ice.
Line B is the mark made when the thermometer bulb is in the steam.

Your physics assignment is to figure out a way to use electricity to launch a small 6.0-cm-long plastic drink stirrer. you decide that you'll charge the little plastic rod by rubbing it with fur, then hold it near a long, charged wire, as shown in figure p23.56 . when you let go, the electric force of the wire on the plastic rod will shoot it away. suppose you can uniformly charge the plastic stirrer to 10 nc and that the linear charge density of the long wire is 1.0 x10-7 c/m. what is the net electric force on the plastic stirrer if the end closest to the wire is 2.0 cm away?