A point charge qı is held stationary at the origin. A second charge q2 is placed at point a, and the electric potential energy of the pair of charges is +5.4 x 10-8 J. When the second charge is moved to point b, the electric force on the charge does -1.9 x 10-8 J of work. Part A What is the electric potential energy of the pair of charges when the second charge is at point b? Express your answer in joules.

Part A How far must the point charges qi = 7.10 µC and q2 = -26.1 µC be separated for the electric potential energy of the system to be -166 J ? r = cm Submit Request Answer Provide Feedback Next >

Part A To what potential should you charge a 1.0 F capacitor to store 1.0 J of energy? Express your answer in volts. AE中 ΑΣφ ? V = Submit Request Answer Provide Feedback

A parallel-plate capacitor is charged by a 9.00 V battery, then the battery is removed. Part A What is the potential difference between the plates after the battery is disconnected? Express your answer with the appropriate units. V = 9.00 V Previous Answers Correct Here we learn how to determine the potential difference between the capacitor's plates after the battery is disconnected from it. Part B What is the potential difference between the plates after a sheet of Teflon is inserted between them? Express your answer with the appropriate units. VT = 4.29 V Submit Previous Answers Request Answer iew?assignmentProblemID=192449649

Item 29

Attached is question, multiple choice.

Electrostatic forces are conservative. This means that mechanical energy (KE +PE) is constant or conserved in absence of other dissipative forces such as friction. If a charged particle moves from point A to point B in an electric field (assume that dissipative forces such as friction are absent), select all the statements that are true. The symbol A represents the change in the particular quantity. Recall what does positive and negative work mean? Reflect on what the negative sign represents in each case? Select multiple answers. APE=-Work A→B i.e., for positive work, PE decreases and for negative work, PE increases ΔΚΕ # -ΔΡΕ ✓ changes in KE and PE are not connected. ΔΚΕ = -ΔΡΕ i.e., if KE increases, PE decreases and vice-versa APE=WorkAB Ⓒi.e., for positive work, PE increases and for negative work, PE decreases

Electric Potential Energy (An lonic Crystal) 3. Four positive and four negative charges of equal magnitudes +Q are arranged alternately on the corners of a cube of side length d, +Q as drawn. This is a model of one cell of an ionic crystal such as -Q +Q salt, NaCl. a. Calculate the potential energy of this configuration. As d usual, take the energy to be zero infinitely far away from the charges. Express the energy in terms of k, Q, and d. d Hints: -Q +Q There are 12 pairs of opposite charges along the edges There are 12 pairs of like charges along the diagonals of each face There are 4 pairs of opposite charges along the cube's long diagonals b. In part (a), you should have determined that U < 0. Explain the relationship between this result and the observation that such crystals freely form in nature.

Part A An isolated 4.40 µF parallel-plate capacitor has 4.20 mC of charge. An external force changes the distance between the electrodes until the How much work is done by the external force? capacitance is 2.40 µF. Express your answer with the appropriate units. HA W = Value J %D Submit Previous Answers Request Answer X Incorrect; Try Again; 5 attempts remaining Return to Assignment Provide Feedback

A positively charged ball is dropped into a tube with another positively charged ball at the bottom. It falls a certain distance before turning around. Draw an energy bar chart consistent with this. Take the initial point to be at the top immediately after release and the final point where it turns around. Write an energy equation for this situation, indicating various distances on a sketch. State what your system is and any assumptions you needed to make. Draw qualitatively accurate force diagrams for the dropped ball for the initial and final positions. Write Newton’s 2nd Law equations for the initial and final positions