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(II) Particles of charge +65, +48, and -95 uC are placed in a line (Fig. 16鈥�52). The center one is 0.35 m from each of the others. Calculate the net force on each charge due to the other two.

(II) Three positive particles of equal charge, are located at the corners of an equilateral triangle of side 15.0 cm (Fig. 16鈥�53). Calculate the magnitude and direction of the net force on each particle due to the other two.

(II) A charge Q is transferred from an initially uncharged plastic ball to an identical ball 24 cm away. The force of attraction is then 17 mN. How many electrons were transferred from one ball to the other?

(II) A charge of 6.15 mC is placed at each corner of a square 0.100 m on a side. Determine the magnitude and direction of the force on each charge.

(II) At each corner of a square of side l there are point charges of magnitude Q, 2Q, 3Q, and 4Q (Fig. 16鈥�54). Determine the magnitude and direction of the force on the charge 2Q.

(II) A large electroscope is made with 鈥渓eaves鈥� that are 78-cm-long wires with tiny 21-g spheres at the ends. When charged, nearly all the charge resides on the spheres. If the wires each make a 26掳 angle with the vertical (Fig. 16鈥�55), what total charge Q must have been applied to the electroscope? Ignore the mass of the wires.

(III) Two small nonconducting spheres have a total charge of \({\bf{90}}{\bf{.0}}\;{\bf{\mu C}}\). (a) When placed 28.0 cm apart, the force each exerts on the other is 12.0 N and is repulsive. What is the charge on each? (b) What if the force were attractive?

(III) Two charges, \( - {\bf{Q}}\) and \( - {\bf{3Q}}\) are a distance l apart. These two charges are free to move but do not because there is a third (fixed) charge nearby. What must be the magnitude of the third charge and its placement in order for the first two to be in equilibrium?

(I) Determine the magnitude and direction of the electric force on an electron in a uniform electric field of strength \({\bf{2460}}\;{\bf{N/C}}\) that points due east.

(I) A proton is released in a uniform electric field, and it experiences an electric force of\({\bf{1}}{\bf{.86}} \times {\bf{1}}{{\bf{0}}^{ - {\bf{14}}}}{\bf{ N}}\)toward the south. Find the magnitude and direction of the electric field.