Chapter 19

IWP Applets for Chapter 19

ID/Type	Web Link or WA Question Code	Local download	Launch from browser	Description
M09a	Coulomb's Law	coulombslaw01.iwp	coulombslaw01.iwp	Two balls of equal mass (see Input for value) are suspended from long strings of equal length. The balls are initially charged to the same value of charge Qo. You can add charge to each ball in increments of the initial charge by clicking on the step button (>>). The number by which the charge on each ball is multiplied is listed as an output. The X- and Y-coordinates of the blue ball are also given as outputs. Determine the value of the initial charge Qo. This requires a net force analysis as well as Coulomb's Law. Once you've determined Qo, check your value by changing the mass to something different. Calculate what the separation of the balls should be for that mass. Then check to see if you're right.
E.19.01c	APB-19-01-09	eforce-04.iwp	eforce-04.iwp	Two charges (red and blue) are fixed in position on the x-axis. The green charge, which is positive, is moved by external means back and forth along the y-axis. The green vector represents the net electric force on the green charge due to the red and blue charges. Run the animation to see how the net electric force changes as the green charge changes position. a. If both red and blue charges are positive, which of the two charges has greater magnitude? b. Why is it impossible for the red charge to be negative and the blue charge to be positive? c. Assume that both charges are positive and that the red charge has four times the magnitude as the blue charge. Where on the x-axis must the green charge be located so that the net electric force on the green charge is 0? d. Now assume that the red charge is positive, the blue charge is negative, and the red charge has greater magnitude than the blue charge. For what positions below is it possible for the green charge to experience 0 net electric force? i. x is less than -0.06 m, y = 0 ii. x is greater than +0.06 m, y = 0
E.19.02c	APB-19-02-07	efield-plot-02e.iwp	efield-plot-02e.iwp	Two charges (red and blue) are positioned on the x-axis and produce an electric field in the space surrounding them. A positive test charge is represented by the green dot. Vectors representing the magnitude and direction of the fields of the red and blue charges and of the net field are shown at the position of the test charge. Running or stepping the animation will move the test charge down the screen, and the E-field vectors will change accordingly. Find three different combinations of red and blue charges (other than the original one) so that the net electric field on the x-axis is 0. How could you give in one sentence an infinite number of combinations of red and blue charges?