Estimate the steady-state flux of atomic hydrogen at 25 °c through a steel vessel of wall thickness 4 mm given that its inside surface is kept saturated with hydrogen at a concentration of 4.2 moles m ; the outside surface is exposed to the atmosphere. the diffusivity of hydrogen in a-iron is d. = 0.1 mm ? s? , q = 13.4 kj mol? . if the vessel contains 20 moles of hydrogen, estimate the hours taken to dissipate all of the hydrogen given that the vessel has a surface area of 2m². comment on why it is possible to store hydrogen gas in iron cylinders for much longer periods. how does dissolved hydrogen affect the mechanical properties of a-iron?

Aman pushes on a trunk with a force of 250 newtons. the trunk does not move. how much positive work is done on the trunk? 0.0 j -250 j 250 j 125 j

Inside of a windmill or a dam is a that is used to transform one type of energy into electrical energy. a. motor b. generator c. transformer d. power pack

Arunner is jogging at a steady 3.6 km/hr. when the runner is 2.9 km from the finish line, a bird begins flying from the runner to the finish line at 14.4 km/hr (4 times as fast as the runner). when the bird reaches the finish line, it turns around and flies back to the runner. even though the bird is a dodo, we will assume that it occupies only one point in space, i. e., a zero-length bird. how far does the bird travel? (b) after this first encounter, the bird then turns around and flies from the runner back to the finish line, turns around again and flies back to the runner. the bird repeats the back and forth trips until the runner reaches the finish line. how far does the bird travel from the beginning? (i. e. include the distance traveled to the first encounter)