Calculate the potential V(r) for r>rb. (Hint: The net potential is the sum of the potentials due to the individual spheres.) Use ϵ0 as the permittivity of free space and express your answer in terms of some or all of the variables r, ra, rb, q, and any appropriate constants.

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

What effects result when there is an impact between earth and an asteroid? check all that apply. a.massive flooding. b.extinction of many life forms.c.major earthquakes change in average global temperature.d. giant dust cloud

How many neutrons does element x if it’s atomic number is 28 and its mass number is 87