Suppose that in a 2-dimensional crystallization process with only one substance, the nuclei do not all appear simultaneously, but rather appear uniformly over space and time at rate λ (nuclei per unit area per unit tim). a crystal only starts growing when the nucleus appears. adapt the k-a model to this situation: i. e., find φ(t). hints: work in a 3-dimensional space (2 dimensions of space and one of ti). consider an arbitrary point p in this space (arbitrary location, arbitrary time). determine the region, r, in this 3-dimensional space in which a nucleus must appear in order for p to lie inside the circle growing from the nucleus. then follow question 3 above.

Atwo-stage air compressor operates at steady state, compression 10m^3/min of air from 100 kpa and 300k to 1200 kpa. an intercooler between the two stages cools the air to 300k at a constant pressure of 350 kpa. the compression processes are isentropic. a) calculate the power required to run the compressor, in kw b) compare the result to the power required for isentropic compression from the same inlet state to the same final pressure.

While studying chemical reactions and conservation of matter, sarah's class conducted a variety of experiments. sarah and her lab partner found the mass of a wax candle and placed the candle in a flask. the students lit the candle and let it burn to completion. all that was left was wax and charred candle wick. per their teacher's instructions, the students found the mass of the products. their data can be seen in the data table. formulate a hypothesis the students could test to explain why the experiment did not support the law of conservation of matter. a) the students could repeat the experiment using different candles; there might have been a flaw in the candle. b) the experiment should be repeatable. the students should run several trials and then take an average of the after mass in each trial. c) the students should have someone in the class check their measurement skills as they repeat the experiment. they may have made an error using the balance. d) the students should burn the candle in a container that has some type of lid so that any gas that is a product of the reaction can be contained and massed. submit

What distance does a car travel as its speed changes from 0 to 20 m/s in 17 s at constant acceleration?