2.2 A water molecule consists of an oxygen atom and two hydrogen atoms. The two 0-H bonds are each
0.1 nm long and form an angle of 107° with each other. Where is the molecule's centre of mass located?
Consider the mass of the oxygen atom to be 16 times the mass of a hydrogen atom, and place your
hydrogen atoms along the x-axis of your coordinate system. (Hint: Draw your coordinate system!).
(15)​

Consider the growth of a 20-nm-diameter silicon nanowire onto a silicon wafer. the temperature of the wafer surface is maintained at 2400 k. assume the thermal conductivity of the silicon nanowire is 20 wm-1k-1 and all its surfaces including the tip are subjected to convection heat transfer with the coefficient h = 1×105 wm-2k-1 and t∞ = 8000 k. when the nanowire grows to l = 300 nm, what is the temperature of the nanowire tip (t (x =