Two planets orbit a far away star as shown. is it possible that both planets experience the same gravitation force from the star? a) no, it is not possible. b) yes, it is possible if the closer planet has less mass. c) yes, it is possible if the closer planet as a smaller radius. d) yes, it is possible if the closer planet orbits the star in a shorter time.

As part of an industrial process, air as an ideal gas at 10 bar, 400k expands at steady state through a valve to a pressure of 4 bar. the mass flow rate of air is 0.5 kg/s. the air then passes through a heat exchanger where it is cooled to a temperature of 295k with negligible change in pressure. the valve can be modeled as a throttling process, and kinetic and potential energy effects can be neglected. (a) for a control volume enclosing the valve and heat exchanger and enough of the local surroundings that the heat transfer occurs at the ambient temperature of 295 k, determine the rate of entropy production, in kw/k. (b) if the expansion valve were replaced by an adiabatic turbine operating isentropically, what would be the entropy production? compare the results of parts (a) and (b) and discuss.

The protons in a nucleus are approximately 2 ✕ 10^−15 m apart. consider the case where the protons are a distance d = 1.93 ✕ 10^−15 m apart. calculate the magnitude of the electric force (in n) between two protons at this distance.

Calculate the numbers of photons having a wavelength of 10.0 mm required to produce 1.0 kj of energycalculate the numbers of photons having a wavelength of 10.0 mm required to produce 1.0 kj of energy