A kettle takes in 2000J of energy per second. It transfers 1500J as useful heat energy and 500J is wasted as sound energy and wasted heat. Calculate the efficiency of the kettle.

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 (in m) of a column of water 1.45 km high for a temperature increase of 1.12°c. assume the column is not free to expand sideways. as a model of the ocean, that is a reasonable approximation, as only parts of the ocean very close to

City b is south of city a, and the 200 mile trip by car takes 4 hours. the cities are 120 miles apart in a straight line. what is the velocity of a trip from city a to city b?

If one object has a large redshift and another object has a small redshift, what can we conclude about these two objects?