A painter and his helper are standing on a scaffold. The painter weighs 400 newtons. The helper weighs 300 newtons. The tension in a rope A is 925 newtons. The tension in rope B is 825 newtons. What Is the weight of the board?

Global warming will produce rising sea levels partly due to melting ice caps but also due to the expansion of water as average ocean temperatures rise. to get some idea of the size of this effect, calculate the change in length of a column of water 1.00 km high for a temperature increase of 1.00ºc. note that this calculation is only approximate because ocean warming is not uniform with depth. (answer in ×10^{-3} −3 m)