What is the angular momentum of a 0.200 kg ball rotating on the end of a thin string in a circle of radius 1.40 m at an angular speed of 11.0 rad/s

An air-filled capacitor is formed from two long conducting cylindrical shells that are coaxial and have radii of 26 mm and 103 mm. the electric potential of the inner conductor with respect to the outer conductor is - 700 v (k = 1/4πε 0 = 8.99 × 109 n · m2/c2) the energy stored in a 1.0-m length of this capacitor is closest to