(a) Find the electric field at the location of qa in Figure 18.54, given that qb =+10.00 µC and qc =–5.00 µC. (b) What is the force on qa, given that qa =+1.50nC?

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)