Sarah and Julie mixed sand and salt. They then added water to the mixture. How will we separate the sand from the salt now? That’s easy, said Julie the salt has dissolved in the water, and the sand has not. Just pour the water off. Where in the Venn diagram would the sand/salt/water fit? A
B
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D

In a heat engine if 1000 j of heat enters the system the piston does 500 j of work, what is the final internal energy of the system if the initial energy was 2000 j ?

Asheet of steel 1.5 mm thick has nitrogen atmospheres on both sides at 1200oc and is permitted to achieve a steady-state diffusion condition. the diffusion coefficient for nitrogen in steel at this temperature is 6 x 10- 11 m2 /s, and the diffusion flux is found to be 1.2 x 10-7 kg/m2 -s. also, it is known that the concentration of nitrogen in the steel at the high-pressure surface is 4 kg/m3 . how far into the sheet from this high-pressure side will the concentration be 2.0 kg/m3 ? assume a linear concentration profile.

At the negative terminal of the battery the electron has electric potential energy. what happens to this energy as the electron jumps from the negative to the positive terminal?