A positive charge of q_{t} = 1.0nC is fixed at x = 0.0 cm * y = 1.2 cm . A negative charge of q. = -1.3 nC is fixed at x = 1.8 cm , y = 0.0 cm . (Hint: nano means 10 ^ - 9 and centi means 10 ^ - 2 Make your signs correct throughout !) a) What are the x and y components of the electric field at the origin due to these two charges? b) What would be the x and y components of the force on a negative charge, q_{3} = - 3.0nc , if it were placed at the origin?

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*