Ahydrogen atom can be considered as having a central point-like proton of positive charge +e and an electron of negative charge -e that is treated as a volume charge distribution around the proton which is given by: p=a*e^(-2r/a) and extends out to infinity. a is a constant, a is the bohr radius, and r is the distance from the center of the atom. a) using the fact that the hydrogen atom is electrically neutral ( meaning that the electron charge distribution must integrate to a charge of -e) find a. b) then, find the electric field produced by the atom at r=a.

Review multiple-concept example 7 in this chapter as an aid in solving this problem. in a fast-pitch softball game the pitcher is impressive to watch, as she delivers a pitch by rapidly whirling her arm around so that the ball in her hand moves in a circle. in one instance, the radius of the circle is 0.626 m. at one point on this circle, the ball has an angular acceleration of 66.1 rad/s2 and an angular speed of 12.6 rad/s. (a) find the magnitude of the total acceleration (centripetal plus tangential) of the ball. (b) determine the angle of the total acceleration relative to the radial direction.