In the simple bohr model of the eighth excited state of the hydrogen atom, the electron travels in a circular orbit around a fixed proton. the radius of the orbit is 4.28 ✕ 10−9 m, and the speed of the electron is 2.43 ✕ 105 m/s. the mass of an electron is 9.11 ✕ 10−31 kg. what is the force on the electron (in n)? (enter the magnitude.)

Consider a small frictionless puck perched at the top of a fixed sphere of radius r. if the puck is given a tiny nudge so that it begins to slide down, through what vertical height will it descend before it leaves the surface of the sphere? [hint: use conservation of energy to find the puck's speed as a func e conservation of energy to find the puck's speed as a function of its height at what value of this normal force does the puck leave the sphere? ] here on the puck.