Q. A proton with speed v = 3.00 x 105 m/s orbits just outside a charged sphere of radius r = 1.00 cm. What is the charge on the sphere?
Q. A loudspeaker of mass 21.0 {rm kg} is suspended a distance of h = 2.40 {rm m} below the ceiling by two cables that make equal angles with the ceiling. Each cable has a length of l = 3.90 {rm m}.
What is the tension T in each of the cables?
Use 9.80 {rm m/s}^2 for the magnitude of the acceleration due to gravity.