A point charge q1 = 4.00 nC is placed at the origin, and a second point charge q2 = -3.05 nC is placed on the x-axis at x =+ 21.0 cm. A third point charge q3 = 2.10 nC is to be placed on the x-axis between q1 and q2. (Take as zero the potential energy of the three charges when they are infinitely far apart.)

Part A:What is the potential energy of the system of the three charges if q3 is placed at x = + 10.0 cm?
Part B:Where should q3 be placed between q1 and q2 to make the potential energy of the system equal to zero?

3. a worker pushes a 30.5 kg polished stone along a polished table with a force on bonin a straight line for 5.20 s after starting from rest. there is no friction between thestone and the table. at the end of the table. the stone is hooked to a cable with a lengthof 62.0 cm to rotate it to a rough table to store until they can be picked up. the roughtable has a coefficient of static friction 0.702 with the polished stone. remember that 8= 9.80 m/s2a) what is the speed of the stone when it is hooked to the cable? b) what is the tension in the cable while the stone is rotating? (there is still nofriction)c) how much force is needed to make the stone begin sliding from rest on therough table? ius = 0.70262.0 cm30.5 kg20.5 kg6= 0