Acharge of +q is fixed in space. a second charge of +q was first placed at a distance r1 away from +q. then it was moved along a straight line to a new position at a distance r away from its starting position. the final location of +q is at a distance r2 from +q.
what is the change in the potential energy of charge +q during this process?
kqq/r
kqqr/r12
kqqr/r22
kqq((1//r1))
kqq((1//

Asteel tube (k=50 w/mk) of inner and outer diameter di = 20mm and do=26mm, respectively, is used to transfer heat from hot gases flowing over the tube (h-hot = 200w/m2k) to cold water flowing through the tube (h-cold = 8000 w/m2k). what is the cold-side overall heat transfer coefficient uc? to enhance heat transfer 16 straight fins of rectangular profile are installed longitudinally along the outer surface of the tube. the fins are equally spaced around the circumference of the tube, each having a thickness of 2mm and a length of 15mm. what is the corresponding overall heat transfer coefficient uc? *solve for uc in both cases*