Both hydrogen gas and helium gas are lighter than air. why is helium used to lift blimps instead of hydrogen? a. helium has more lifting force than hydrogen because it has more electrons. b. hydrogen has less lifting force than helium because it has less mass. c. hydrogen has a tendency to lose an electron, decreasing lift. d. helium is more chemically stable than hydrogen and will not burn.

Abeam has a square cross-section, a x a, where a is the linear dimension, and is subject to a pure bending moment, m. m is known with an uncertainty of 10% and a is known with an uncertainty of 5%. the strength of the material is known to an uncertainty of 12%. find the minimum design factor such that the beam is guaranteed not to fail.

Asteam power plant operates on an ideal reheat rankine cycle between the pressure limits of 15 mpa and 10 kpa. the mass flow rate of steam through the cycle is 12 kg/s. steam enters both stages of the turbine at 500°c. if the moisture content of the steam at the exit of the low-pressure turbine is not to exceed 10 percent, determine (a) the pressure at which reheating takes place, (b) the total rate of heat input in the boiler, and (c) the thermal efficiency of the cycle. also, show the cycle on a t-s diagram with respect to the saturation lines. (2.15 mpa; 45.0 mw; 42.6%)

The least penetrating form of radiation is