Calculate the force of gravity on a 4 kg mass at Earth's surface. The mass of the Earth is 6 x 1024 kg and its radius is
6.4 x 106 m. Do not use scientific notation. Round to a whole number (no decimal).

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 =