Two sumo wrestlers run towards each other, the first has a mass of 150kg and is running at 14m/s. The second wrestler has a mass of 200kg and is running with
a speed of 18m/s. They collide in a perfectly elastic collision. If the second
wrestler bounces backwards at 4m/s. Find the final velocity of the first wrestler.

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 =