A 73.0 kg father and his 45.0 kg son are sitting on opposite sides of a 4.00 m seesaw at the playground. The pivot point is fixed at the mid-
point of the board. Where must the father position himself to horizon-
tally balance the seesaw if his son sits at the end of the board?

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

Which is a substance that can be separated by physical means and is not the same throughout

Which system of units is used by only a small number of countries in the world, including the u. s.