Q1. Determine the amount of electrostatic energy of a uniform sphere of charge with radius b and volume charge density ρ stored in the following regions: i) inside the sphere. ii) Outside the sphere

Q2. In March 2004, a British company effectively tested a power system to tap the energy of ocean tides. The energy will be stored in an underwater turbine consisting of two metal blades, each 15.0 {rm m} long. The movement of the water because of the tides will give kinetic energy to the turbine blades, causing them to spin. In the calculations that follow ignore any frictional drag because of the seawater.

If we model each of these two blades as a thin uniform steel bar 15 {rm m} long and 25 {rm cm} in diameter, at what rate (in {rm rad/s} and {rm rpm}) must they spin for the turbine to store 1.00 {rm MJ} of energy? The density of steel is 7800 {rm{{rm kg}/{rm m}}}^3 . (Recall that density is equal to an object's mass divided by its volume?