Please answer all of the following questions. 22 QUESTIONS IN TOTAL

Name Date Coulomb's Law Lab Report Prelab question: 1) Two point charges have a total charge of 560 C. when placed 1.10 m apart, the force each exerts on the other is 22.8 N and is repulsive. What is the charge on each? 2) Solve problem 16 on page 469 of your Text Book. 16. (II) A large electroscope is made with "leaves" 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 angle with the vertical (Fig. 16-55), what total charge @ must have been applied to the electroscope? Ignore the mass of the wires. 26 26 78 cm 78 cm FIGURE 16-55 NIKO NINO Problem 16.Lab Questions: 1. What then can you say about the charges on the pith balls in Figure 3a? 2. Each pith ball is hanging at rest. What are the two (external) forces acting on, say, the left ball in Figure 3a? Strong nuclear, weak nuclear, friction, gravity (its weight), electrostatic, tension, air resistance (Circle two) 3. How do the magnitudes and directions of these two forces compare? (They are not accelerating.) The forces are and 4. Draw a FBD for the right-hand ball in Figure 3a using the dot provided. Use the same scale as the FBD on the left ball. USE A PENCIL. In figure 3b the balls have been equally charged. Both are hanging at the same angle, 0 either side of the vertical line. 5. Keeping the same scale, add a weight vector to the right ball's FBD. (Ignore the weight of the excess electrons.) 6. The ball is in equilibrium, so there still must be an equal upward force. In figure 3a that force was the tension force. But the tension is no longer acting in the upward direction. It's now acting in a direction of 0 degrees relative to the vertical. The upward force is the y-component of the tension, Ty. Draw this vector and label it Ty. Be careful with your scale. 7. You now have T's y-component. From it you can draw the actual tension vector, T. Carefully add it to the FBD. 8. Explain how you knew how long the vector T should be. 9. Add the angle 0 to your FBD. 10. You now have T and Ty on your FBD. Clearly there is a horizontal component of T, Tx. Add that to your figure. Draw it with its tail starting at the dot. Again, be careful with your scaling. We now have W, T, Ty, and T, in our FBD. Are all these forces acting on the pith ball? Not exactly. We have some redundancy. T is the vector sum of Tx and Ty. So T has actually been replaced by its components. 11. Draw a "~" through the T vector to indicate that we can ignore it now. 12. Look at our remaining three vectors. Does our FBD indicate that the ball is in equilibrium? 13. What type of force, missing from our FBD, is keeping the ball in equilibrium?Strong nuclear, weak nuclear, friction, gravity (its weight), electrostatic, tension, air resistance (Circle one) 14. Add that force vector to your FBD and label it Fe. Draw it with its tail starting at the dot. Again, be careful with your scale. 15. Draw the matching FBD for the left ball. Table 1 Charge on a Pith Ball (you may not actually need all of these values) k = 9.0*109 N m2/C2 mass of a pith ball (from lab info box), m = _ kg charge # = accepted value for charge on one pith ball (info box), Qa = C experimental value for charge on one pith ball, Qe = C separation between centers of pith balls, r = m length of the pendulum, L = m deflection angle of a pith ball from the vertical, 0 =1. Explain your method in words, referring to labeled Figures. (You supply the figures.)2. Clearly show your calculations using the proper variable terminology. Include the calculation of percentage error for your value ofthe charge on. a pith ball. 3. What do you feel was the major source of error? Why? 4. Is the assumption that the charge distribution is spherical most inaccurate for small or lager? Explain. 5. Redo the calculation for the charge on pith ball if the mass of pith ball was 0.075 gram