A parallel-plate capacitor is constructed with circular plates of radius 6.0×10−2m . The plates are separated by 0.26mm , and the space between the plates is filled with a dielectric with dielectric constant κ. When the charge on the capacitor is 1.3μC the potential difference between the plates is 780V . Find the value of the dielectric constant, κ. A charge of 2.55μC is held fixed at the origin. A second charge of 2.55μC is released from rest at the position (1.25 m, 0.570 m). If the mass of the second charge is 2.41g , what is its speed when it moves infinitely far from the origin?