A student hangs a balloon from a string then rubs it on their hair and releases it. They rub a second balloon on their hair then move it towards the hanging balloon the moving balloon moves away because ..
A) like charges attract each other
B)unlike charges repel each other
C) like charges repel each other
D)unlike charges attract each other

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)