7. Four identical point charges (+6.0 nC) are placed at the corners of a rectangle which measures 6.0 m x 8.0 m. If the electric potential is taken to be zero at infinity, what is the potential at the geometric center of this rectangle? a. 58 V b. 63 V C. 43 V d. 84 V e. 11 V 8. A particle (charge = Q) is kept in a fixed position at point P, and a second particle (charge = q) is released from rest when it is a distance R from P. If Q = +2.0 mC, q = -1.5 mC, and R = 30 cm, what is the kinetic energy of the moving particle after it has moved a distance of 10 cm? a. 60 KJ b. 45 KJ C. 75 KJ d. 90 KJ e. 230 KJ 9. Two particles, each having a mass of 3.0 mg and having equal but opposite charges of magnitude 5.0 nC, are released simultaneously from rest when the two are 5.0 cm apart. What is the speed of either particle at the instant when the two are separated by 2.0 cm? a. 2.1 m/s b. 1.5 m/s C. 1.8 m/s d. 2.4 m/s e. 3.2 m/s 10. Identical point charges (+50 p/C) are placed at the corners of a square with sides of 2.0-m length. How much external energy is required to bring a fifth identical charge from infinity to the geometric center of the square? a. 41 J b. 16 J C. 64 J d. 10 J e. 80 JA charged particle (q = 8.0 m0), which moves in a region where the only force acting on the particle is an electric force, is released from rest at point A. At point B the kinetic energy of the particle is equal to 4.8 J. What is the electric potential difference VB VA '? a. 0.60 kV b. +0.60 kV c. +0.80 kV d. 0.80 kV 9. +0.48 kV What is the speed of a proton that has been accelerated from rest through a potential difference of 4.0 kV? a. 1.1x106m/s b. 9.8x105m/s c. 3.8x105mrs d.1.2x106m/s e. 6.2x105m/s A proton (mass = 1.67 x 1027 kg, charge = 1.60 x '1019 C) moves from point A to point B under the influence of an electrostatic force only. At point A the proton moves with a speed of 50 km/s. At point B the speed of the proton is 80 kas. Determine the potential difference VB VA. 3. +20 V b. 20 V c. 27 V d. +27 V e. 40 V An electron (m = 9.1 x 1031 Kg, q = 1.6 x 10}'9 C) starts from rest at point A and has a speed of 5.0 X '106 mfs at point B. Only electric forces act on it during this motion. Determine the electric potential difference VA VB . a. 7'1 V b. +71 V c. 26 V d. +26 V e. 'l40 V Point charges q and Q are positioned as shown. If q = +2.0 nC, Q = 2.0 nC, a = 3.0 m, and b = 4.0 m, what is the electric potential difference, VA VB ? a. 8.4 V b. 6.0 V c. 7.2 V d. 4.8 V e. 0 V A +4.0-MC charge is placed on the x axis at x = +3.0 m, and a 2.0-pC charge is located on the y axis at y = 1.0 m. Point A is on the y axis at y = +4.0 m. Determine the electric potential at point A (relative to zero at the origin). a. 6.0 W b. 8.4 W C. 9.6 kV d. 4.8 W e. 3.6 kV 10. 11. 12. 13. Four identical point charges (+6.0 nC) are placed at the corners of a rectangle which measures 6.0 m >