QUESTION 14 If two electrons are placed each 2.11E-10 m from a proton as shown, What is the magnitude of the net electrical force they exert on the proton (in Newtons)? QUESTION 17 An electron is circularly orbiting a proton. The magnitude of acceleration of the electron is 6.21E8 m/s2. What is the electron's orbital radius (in meters)? QUESTION 18 A metal ball initially carries a net charge of +7.63E-7 C. To change the ball's net charge to +1.45E-6 C, What is the charge that needs to be taken off from the ball (in Coulombs)? QUESTION 20 Sphere A having a net charge of +2.50E-6 C is placed on a scale, which measures its weight in Newtons. Sphere B having a net charge of 6.40E-6 C is directly positioned 9.79 m above the rst sphere, and the reading of the scale is found to be zero. What is the mass of sphere A (in kg)? QUESTION 21 On the x axis, a point charge Q = +4.55E-6 C is placed at the origin x = 0.00 m. What is the electric eld E at x = 6.29 m (in N/C; use positive sign if E points in the +x direction, and negative sign if E points in the x direction)? QUESTION 22 On the x-y plane, a point charge Q =-2.83E-6 C is placed at the origin (0.00 m, 0.00m). The electric field at (x,y) = (2.40 m, 3.20 m) is measured to be Q = Ex , + Ey ? . What is the electric field's y component Ey (in N/C)