Arocket (initial mass m 0) needs to use its engines to hover stationary, just above the ground. (a) if it can afford to burn no more than a mass am oof its fuel, for how long can it hover? [hint: write down the condition that the thrust just balance the force of gravity. you can integrate the resulting equation by separating the variables t and m. take v„ to be constant.] (b) if v

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)