A metal sphere with radius ra is supported on an insulating stand at the center of a hollow, metal spherical shell with radius rb. There is charge + q on the inner sphere and charge − q on the outer spherical shell as shown below. Take the potential V to be zero when the distance r from the center of the spheres is infinite.(Figure 1) 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.

Most energy in an ecosystem comes originally from_

In 1995 a research group led by eric cornell and carl wiemann at the university of colorado successfully cooled rubidium atoms to the 20-200 nk temperature range. assuming (incorrectly) that the rubidium atoms behave liké particles of a classical ideal gas, calculate the rms speed of a rubidium atom at a temperature of 112.0 nk. in the experiments one particular isotope of rubidium was used, rubidium-87. the molar mass of this isotope is 86.91 q/mol. tries 0/20 submit answer

Simon is writing a story about an astronaut whose spacecraft has been boarded by space pirates. the astronaut has her lucky penny in her hand behind her back as the space pirates break into the control room. she has just locked the controls so that the ship is accelerating in the direction of the control room’s ceiling. simon wants the astronaut to use the penny to hit a button on the control panel to turn off the lights and escape. the button is located a short distance behind and below the astronaut’s hands. how should simon use the theory of relativity to describe what the astronaut must do in order to hit the button?