Ageologist finds fossils and rock that are older than the fossils and rock in the layer of earth directly beneath them. what caused this situation?
a. uplift
b. overturning of sedimentary rocks
c. intrusion of igneous rocks
d. seafloor spreading
e. subduction

After an atomic bomb has been dropped, the damage continues to get worse. why is this?

Atomic nuclei of almost all elements consist of

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.