How much work is done by a babysitter who uses 8000 W of power to lift a baby in 2s?

What property is a characteristic of a substance that can be observed and does not change the identity of the substance

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)

If anyone who can me with this hw? i would really appreciate it