Three charges Q:nC rcm rem 608 60 QZ nC QZ nC In the above figure @; = 1 nC, Q2 = 2nCandr =4 cm. a) What is the electric potential energy of this system of charges? Assume that the potential energy is zero when the charges are infinitely far apart. Enter your answer in J to three significant figures without units. b) Assume that the negative charge is released from rest while the positive charges are held in place. If the mass of the negative charge is 1 X 1079 kg, what is its speed when it is at point P, in the middle between the two positive charges? Use your answer from part a) to find this. Enter your answer in m/s to three significant figures without units. c) Can you calculate the speed of the electron using our "old" (kinematic) approach? You may need the following formulas: 7 (t) = 7; + Tt + dt? /2, vfe = v? + 2@ - 7. What do you get? v Select an option a Yes, | can use the kinematic approach. My answer is the same as in part b). | got a different answer. This means that the kinematic approach does not work here. | got a different answer. This means that the work-energy principle does not work here. Hini