P 91 - x(m) -0.20 0.20 0.40 0.60 3. Two point charges q1 and 92, are placed 0.30 m apart on the x-axis, as shown above. Charge q1 has a value of -3.0 x 10"" C. The net electric field at point P is zero. a. What is the sign of 92? Justify your answer. b. Calculate the magnitude of charge 92. c. Calculate the magnitude of the electric force on 92 and indicate the direction. d. Determine the x-coordinate of the point on the line between the two charges at which the electric potential is zero. e. How much work must be done by an external force to bring an electron from infinity to the point at which the electric potential is zero?3.0 0 S Bulb A 9.0 V 6.00 2 3.0 0 Bulb B Bulb C 4. Lightbulbs of fixed resistance 3.0 02 and 6.0 0, a 9.0 V battery, and a switch S are connected as shown in the diagram above. The switch S is closed. a. Calculate the current in bulb A. b. Which lightbulb is brightest? Justify your answer c. Switch S is then opened. By checking the appropriate spaces below, indicate whether the brightness of each lightbulb increases, decreases, or remain the same. Explain your reasoning for each lightbulb. i. Bulb A: increase decrease remains the same ii. Bulb B: increase decrease remains the same iii. Bulb C: increase decrease remains the same5. A particle of mass m = 500 g is attached to a horizontal spring. The particle executes a simple harmonic motion and the displacement x as a function of time t is shown in the figure below. xlom/ 10.0* 2.00 4.00 6.00 8.00 10.0 Fig. 3 -10.0+ Find the: (a) Period (b) Amplitude (c) Equation of motion (the position as a function of time) (d) Maximum velocity (e) Maximum acceleration (f) Spring constant k (g) Total energy (h) Speed of the velocity when x = 5.0 cm